Tiny black piece of tick still in my dog?

Are you possitive it was a tick? I have a pit and we thought he had a tick so we actually went to get it pulled out and he yellped bad so I said nope off to the vet we come so took him to the vet the vet thought he pocked it on a branch and gave meds and nothing went away so went back to come find out he had a cancer pocket... he had it removed and living good now