My chinese money plant has these weird little spots. Some leaves just have the brown rash looking patch, but the one has a dark solid spot that seems to have almost made a hole. this is the second time i've seem spots/patches like this. the stems are also pretty limp, which is abnormal for this guy. There are no visible bugs. I've been a bit neglectful this month, and he was underwatered. I would appreciate any help
It looks like your plant has a small case of Oedema. Oedema is when the roots takes up water faster than it can use it or loose through transpiration. It causes a blister. The blisters of oedema look different on different plant. This happen when you over-water your plant.
You should cut back on watering and how much water you give your plant when you do water. You should make sure your plant really needs water before watering it again. One of the easiest methods to uses is the use of a bamboo barbecue skewer. Insert the skewer into the soil, in 30 mins check the skewer. Look at it and touch it. If it is wet do not water your plant, check back again in a few days. If it is dry you should water your plant, but don't give it too much. Give it enough water that the water starts to come out of the bottom of the pot. If the soil is extremely dry, it might repel the water at first and it will run right through the pot without wetting the soil. IF that happens, try to water it again in 10 mins. With time you, you will be able to read the skewer better and know what is too moist. This takes time. The key is not water water if the soil is already wet. Best to let the soil dry out, but not dry out too much. Pilea will start to droop if they are dry.