The first thing we need to establish is what type of potting mix your plant is growing in. Watering every two or three days is far too often for soil or peat/coir based mixes and I suspect that you caused the roots to suffocate and then rot. once this process starts it is very difficult to turn things around by watering less.

Can you tell us how the plant looks now? Are the leaves still smooth or are they beginning to wrinkle? It may be necessary to start your plant again from cuttings if the root system has died. Repotting would be necessary in my opinion and we can help you to make a potting mix that will be suitable.

Mike

Thanks for the response!

The potting mix is what came with the plant, I am not sure what type they used. It came from a fairly legitimate hardware store in my area and I would assume that they used the correct mix. It looks like a peet moss mix, though I am not entirely sure. The leave are still smooth and there is still new growth, but they are beginning to wrinkle towards the base.

As Mike suggests, there is probably root damage to your plant. Most Hoyas you would buy somewhere like a hardware store are not a single plant, but many separate plants with their own root systems. So, there are likely some that died off early and others that are still hanging in there. The question is whether those that are still alive are going to pull through or if their roots are so damaged that they are going to continue dying even though you fixed your watering schedule. In the latter case, they need to be re-rooted.

I would suggest that you at least take some cuttings of healthy looking sections and stick them in a separate pot or the same one, to develop new root systems. I think you have much better odds doing that than waiting to see if the main pot will recover. You can also take a picture of the plant, because it will be easier for us to tell how big the problem is from a picture than from your subjective description.

Roughly once a week is a good pace for soil of that type, but really you want to measure it not based on time, but by feeling the soil. Start out by sticking your finger a couple inches down into the soil and water when it feels dry. You can also get used to how heavy the pot feels when the soil is dry versus when it is wet.

Good luck! I'm really glad you're enjoying your (girlfriend's) carnosa. :)