Had a shave removal of a mole, which was benign, but it grew back. can the removal change the cells to cause it to grow back cancerous?

Get is excised: A mole can recur which is probably the case with you right now. But it can also be a melanoma. I would recommend you going to a surgeon and get this mole completely re-excised and examined by a pathologist so that you will be able to get a formal pathology report just to be sure that you do not have a melanoma which has been treated as a mole, first time around.