How To Treat Pus Filled Pustules On Scalp?

I am suffering from SLE from the last 6 years. About 2years back I had a flare with nepritis. Even since I am on wysalone though the dose now from the last 6-7 months is 2.5 mg. I often get joint pains, and boils with pus on the scalp and other places. How are thse steroid on long term basis going to harm me?
Also what should I do with the frequent outbreak of pus filled pustule which are quite painful?