Don´t worry , it´s not going to die, montsera is a very hardy plant. If indoors see that it doesn´t get sunlight through the window, and avoid direct a/c cold. Could be poor drainage or excess fertilizer. Otherwise, repot in a bigger, wider pot, and add a moss covered tutor to support it and aerial roots. Then water properly and make sure that all the water drains. The damaged leaf will go brown and fall off, but new ones come out all the time. Try to water with soft water - not really that important- and keep the leaves dust free. Remember that it could be adapting still, and IMO, nothing that is living is perfect. :)

wondering when I know it's time to repot? It came in a plastic container (inside the decorative one) that drains very quickly, which I've heard isn't good. OTOH, I've heard they don't like too much room and to wait for roots to stick out the bottom before repotting. 9 of 10 people that give advise on the internet are guessing or repeating advise they read somewhere else - whether it's appropriate or not. It's time to repot at the point in time where (when?) you can lift the root and soil mass from the pot intact. Root congestion probably starts to be somewhat limiting a little before that point, but not seriously, so the "when you can lift the root/soil mass from the pot intact' is simple to remember and simple to verify. I use that as my own reference point. No plant "prefers" to be grown tight. If it did, Mother nature would have arranged for roots to occupy a little pot-shaped root ball directly under the plant's stem. There are sometimes good reasons to allow or use the stress associated with root congestion to achieve an effect or bend the plant to your will, but it's inaccurate to simply announce any plant likes to be root bound. Repotting is different and more involved with potting op. The former includes bare-rooting the plant, pruning roots, and repotting it in a fresh batch of soil. Potting up is little more than putting the plant in a larger pot and filling in the void at the bottom and sides with fresh soil. The former ensures all limitations imposed by root congestion go away; the later ensures limitations imposed by root congestion remain until the time someone actually gets their hands in the root/soil mass to correct the root issues and congestion. This holds true even if the plant were to be planted out (in the landscape). When keeping the best interest of the plant in mind, that you discover it's time to repot isn't reason enough to repot the day after. Timing heavy work like hard pruning and repotting is best done in consideration of the plant's natural rhythms. If you repot a healthy tropical ficus in fall or winter, it might take several months to recover to the point top growth can resume. Repot it in very late spring (early spring is not a good choice), as in just before the summer solstice (I use Father's Day as a reference point) and the plant will be pushing new growth in 1-3 weeks. It's better to allow the plant to suffer some small amount of stress from root congestion and repot when the plant is about to be at its most robust state in the growth cycle than to repot when the plant is just trying to make it until next spring when it's at its best. I would only repot out of season if I knew or strongly suspected the plant would be down for the count before a more appropriate time to repot rolled around. I've been pruning back slowly so as not to shock, pruning in the early fall when I want to incentivize root growth over winter. Usually my ficus drops a lot of leaves over winter (we are in New England). I'm hesitant to do a major trim in the spring because that is when I want to full new growth. How far can I cut the leggy branches back? And how many of them at a time? Perhaps I'm being too incremental in my pruning and not giving it the fresh start it needs. You prune in early fall, then your tree puts on a lot of leggy growth over winter, growth you're reluctant to remove until fall. In fall, you cut off all the desirable short internodes, all the way back to the long internodes. Doesn't that sound backward? What if you pruned in late May? You'd be removing ALL the leggy growth from winter. Then, as new growth with short internodes follows the spring pruning, you pinch until Sep, then don't do any pruning until the following Memorial day. That approach guarantees ALL growth is the tightest the plant can produce within other cultural influences. You saw the growth explosion on the tree I pruned back to only a few leaves (above)? That's 2 months worth of summer growth. Thoughts? Al

Here are photos

Mine seems like the toughest plant. I have had mine maybe 20 years, it's quite large, and I don't even know if there's much soil left in the pot. It goes outside in filtered light when it warms up, gets watered sometimes, and then I bring it in in the winter. It usually dries out in the winter and the leaves might turn yellow and die. This winter it must be getting enough light and water from my cat's partly empty bowls that I toss on the plant. It is still green in a dim bathroom. My point is, once your plant gets established you might not have to fuss over it. I'm not sure how to advise you to get it to survive at this stage. It does look like kind of a fine, dark soil. I do not know what the 5 1 1 soil is but assume it drains better. I voted to pot up in your new soil mix now but have no idea how fast it'll dry out and that's a concern since you're going on a trip. I think the original potting soil I used was MIracle Grow.