Can the lip lift be done intraorally? I develop scar tissue after any surgery and do not want to risk it.

Liplift is a wonderful procedure for various conditions associated with long upper lip shadowing the teeth.  
If the red mucosa of the upper lip is long it certainly can be shortened with incision inside the lips rather than incision on the outside of the lip. But if the upper lip is long , covering the teeth of the maxilla, upper jaw, than an incision would best be done right at the junction with the nose on the outside skin. Adding dermabrasion to this makes the healing faster and better minimizing the scars to minimal.  
Sometimes adding laser resurfacing can further help to get better harmony in this delicate area. 
Good luck to you