i met this girl and she was keep telling me she is allergic to something but she doesnt know. she doesnt have enough money to do the tests and stuff like that. first she will ask money to me but later on she hit me one time and when she wanted to hit again i hold her wrist and put little bit pressure than after couple seconds her wrist turn to red i was almost freaking out, i mean there is no way with that pressure u can have a red skin like that. she said that this thing started to her like 3days ago also it happened to her sister as well it went away. anyway i am so wondering what might be this red skin thing

You need friends who do not hit.
Some people simply have extremely sensitive skin and even mild pressure or a slight abrasion can cause irritation.