What Causes Bump On Penis Under Foreskin?

My foreskin had dry blister like areas on it-|I applied some cortisone cream to this and my foreskin became very red and swollen. I can still retract my foreskin to void but I now notice a small bump on the right side of my penis under the foreskin which seems to pull my foreskin to one side when I pull it back. what is this bump? have applied ice with some relief. What else should I do?