GSP hasn't taken much damage at all. He just bruises VERY easily. The very few times his face has looked busted up, he got hit like 10 times. Having a black eye doesn't mean you take a lot of punishment. He just has very thin skin apparently.
He's had a lot more UFC fights than Khabib. If Khabib stayed for 10 more fights, his career would definitely look worse than GSP's.
I mean, GSP was in the UFC in his SIXTH fight. Khabib was crushing cans and beating a 0-0 amateur in his FIFTHEETH fight.
I just can't see Khabib winning 7 more fights in the UFC without losing or taking any damage. Consistency is the hardest part of the game, and the reason fighters like GSP, Jones and Silva are soo far above anyone else in GOAT talks and achievements.