Hi,I Have Been Getting Pimples On My Face But The

Hi,I have been getting pimples on my face but the problem is they're filled with blood and so they look like dark red spots.Actually every 3 or 4 month I get 1 or 2 of them and they last for a month or even more.They are terribly painful when I touch the areas around them and they are also swollen.I decided to squeez one to see what is inside it and after squeezing it hard it started bleeding and the blood was dark red.Then it was ok and changed to a very small spot.I just want to know if there is a serious problem?and why have I got them?