I’m the same way. I love cuddling, hugging, and being held in general, but sometimes I get like you and being touched makes my skin absolutely CRAWLS. It sucked when I actually had a gf who would spend the night and then we couldn’t cuddle all night :c I’m jealous your girlfriend is like that, it sounds adorable, but if you can’t take touch, I can see why that’d be bad. Yeah, I can see why she’d think it’s a game.
The best way to talk to her about it would to be to explain that with your Autism, or whatever part of the spectrum you may have, you may or may not have a hyper sensitivity to any the 5 senses to one extreme or the other. And tell her you have a sensitivity to touch, and try to explain to her the best you can what it is like and why you do not like it. Draw extremely clear lines of what is okay and what is not okay, and make ABSOLUTELY clear you let her know it’s your Autism and it has nothing to do with her.
As long as you are completely honest and very clear about boundaries, everything should work out. But kissing is an extremely important part of a relationship to most people, so you should try, over time of course, to kind of get used to it. I used to be extremely bad with my skin crawling, but I forced myself to learn to like it because I personally like it whether my Autism does or not. That is completely up to you whether you do that or not, but I imagine it would mean a lot to her if you tried.
Hope that helped! Let me know how that goes or if you need any advice regarding getting used to touch. :)