Is this normal for a dog?

My dog had this lump that the vet said was a small harmless cyst but that I could pop it if needed. It has been irritating him lately because he’s been biting at it. I decided to pop it today. (ps. this lump is the size of a quarter). When i popped it, and unimaginable amount of thick whiteish pus came out. and it just kept coming out. Then there was a fairly large hole on the surface of his skin that then was clotted with blood.
Is it normal for so much thick pus to come out?
Can i stop this from coming back?