Hello, I Have Bumps That Appear And Dissappear. They Show

Hello, I have bumps that appear and dissappear. They show up and stay raised under my skin for about a minute and then they dissappear. They don't particularly itch and they are not red or inflamed. They occur very rarely but then again I have no way of noticing them unless I am looking at myself when they show up. I have seen them on my forearms and legs