Once a fixed drug eruption occurs, it will recur whenever the incriminating agent enters your body. During the active phase there will be discomfort; even ulceration can take place. Thereafter hyper pigmentation will follow which will take time to disappear. To my mind persistent bumps should not be there. If so then you have some additional problem which has to be diagnosed and managed accordingly.
I suggest you take another opinion, maybe also from a surgeon, for the bump in the anal area. It is possible you have external piles also.