Since the rash has been present for 3 months, the possibility of eczema skin and psoriasis needs to be ruled out. Psoriasis is a long-term (chronic) skin problem that causes skin cells to grow too quickly, resulting in thick, white, silvery, or red patches of skin. It is thought that psoriasis occurs when the immune system overreacts, causing inflammation and flaking of skin.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.