I tried to raise my charisma by one point so that I could unlock campfire scenes with Trudy and kylira but I can't seem to raise my charisma naturally . I tried levelling up and I used my perk points on "hotter" but it only worked once even though I leveled up again and got more perk points I can't use them on the same perk. How do  I increase charisma without buying special armor? Also can I increase all my stats that I started with?

Each perk level requires one more perk point than the last, so to get another Hotter rank you'll need 2 perk points.

1) About perks: you spend 1 perk point for learning a perk once, 2 for the second time, 3 for the third time. 

2) You can raise your Charisma by +1 with the Lacy Panties (cost 100 gold) and the Charisma Charm (200 gold). They also can be stolen.

3) You can get more stat and perk points when creating a new character. Further explanation can be found here.