I believe I have a sebaceous cyst . It normally looks flesh colored and small, but last Friday it became inflamed, red, and swollen. I went to ER and they didn t drain it, but put me on Bactrim . My last pill was last evening and the bump is still there, but is a little smaller and looks like its starting to peel. After getting out of the shower, I put some hydrogen peroxide on a q-tip and put it on the bump and some yellow stuff started coming out, but not alot. I have now put some antibiotic ointment on it and not sure if it s healing or if I need to go back to doctor.