Help me save my plant!

Oh boy... You may have lost this one. Small plants usually struggle in dense, nutrient-loaded soil (never go 100% compost). As Roberts said, perlite (or vermiculite) is the way forward. A 50/50 compost/perlite mix is great. A plant like this only needs a few ml of water daily to live - and be careful to not pour the water directly underneath the stem - roots want to breate and it is VERY easy to drown your plant at this point. I cannot tell for sure whether it is over or underwatering but if you touch the leaves and they are dry and crispy it is underwatering, if they feel very limp but not dry it is overwatering... Usually it is the latter. Wish you all the best!

Looks like it got too dry should be watering to where all of soil gets wet. So having a high perlite amount in soil is very important. Should get run off 10 to 20 percent on watering is recommended.