I Have A Quarter Sized Raised Pimple Like Bump On

I have a quarter sized raised pimple like bump on my butt. When i squeezed it a lot of blood went everywhere and blood keeps coming out some of the blood also seems to form thick drops almost like a clot of blood anytime pressure is put on it even pressure from a light touch. When i took a picture the bump is dark reddish purple. Should I be concerned? I just had my gallbladder taken out a day ago and don't want to risk any infections spreading to the surgical wounds.