Those roots don’t look very healthy. Roots should be white so unless there is a lot of dirt left on them they don’t look good to me and probably there is root rot. Do the roots feel soft and mushy, do they easily come apart if you tug on them? Pothos root pretty fast. If you want to try and save the plant, I would cut off all the brown roots and put the plant back in water to root again. If you are going to use miracle grow I would add perilite to the soil otherwise it retains too much water. Once back in soil, don’t fertilize until it puts out new growth. Hope this help. Ellen

Thank you @Ellen Bshaw! I have cut off all the roots and have just let the plant sit in a plastic bottle of water. I hope this will allow the plant roots to grow back! I'm putting the plant by the window to get some more light!

Yes you are welcome! It there is a node on the stem it will grow new roots