What Causes Small Bumps On The Thighs And Wrists?

hi doctor. i believe you will give me the best answer! i am using melacare since 5 years. but i have not continuued throughout. i used for a month and let for a month and re- started it. and what i notice is that, whenever i start using melacare, there were lot of pimples and bumps around my bumps, inner thighs, and my wrists. my thighs got black along with circle kind of thing.. i consulted so many doctors, they always gives antibiotics. when i consume i felt better, when i stopped it began again. why this is happening with me? i need my fair skin and also my skin problems should be sorted out. kindly help me.