Trump can pardon himself from federal prosecution but it does not exempt him from impeachment or state prosecution, and would cause an unprecedented constitutional crisis.
It could embolden Democratic state(s)
(notably New York) to try and bring some sort of criminal action against him, and I'm somewhat unsure of exactly how much Republicans in Congress would tolerate from Trump at that point. I don't think anyone can say for sure, as Trump pardoning himself and others around him to avoid criminal liability would be completely uncharted territory. I think it is possible he could get tossed out as Republicans know a more stable/reliable Pence is waiting to take over.