Suggest Remedy For Bumps On Forehead

i am 38 year female. had open heart surgery to fix valve 10 yrs ago. since last 3 years i am on 10mg lisinopril to control blood pressure. it was in past decemer one morning i noticed a quarter size bump on my forehead that disappeared in 2-3hours. now since last 2 weeks i see large bumps on my forehead not at consistent place when i wake up in the morning. it goes away in 2-3 hours. please help me. what is this? what should i do?