Paul made attack comments during the debates of both Trump and Christie. He didn't do himself any favors. Yes, he is a "different kind of Republican". That comment and the spar between him and Christie and his rolling his eyes is what I remember. IMHO Paul did nothing but bring a negative image of himself.
Paul will make it to the next debate, but he needs to convey a positive message and rebuild his image. If he can't accomplish that, I think he's done.