For the past 3+ years randomly i get a red soft big pimple/sore on inside of leg. doc says abscess. could that be true? it hurts when it comes and sta

Big red pimple: If it is an abscess, after three years it is time to treat it with an incision ,drainage and antibiotics

Sebaceous cyst: A recurrent lesion in the same location probably would be a inflamed sebaceous or epidermoid cyst. If it keeps bothering u then I would have it excised. An abscess would be very painful and need surgical drainage and/ or antibiotics directed against staph

Yes: If so, an oral antibiotic may be helpful.