Ugh, sorry to hear you are having this reaction. So, it is just recent that you are having this skin reaction? Did a doctor prescribe this for you? Here's some information. https://www.webmd.com/drugs/2/drug-3503/minoxidil-topical/details If you have a doctor who recommended or prescribed this, I think you need to let them know. If you don't and were self medicating, I would check in with whatever pharmacy you have used in the past. The pharmacist can give you some advice. It doesn't really sound like either an infection or eczema but rather a reaction which would be like an allergic reaction. Odd that it took 4 months to happen. So, the other possibility is that it is drying your skin out. You don't say it itches. I have read that skin irritation, dryness and even pigment changes such as you describe are the side effects of minoxidil though. Is it really noticeable?