Hello,I am 15 years old boy,and i recently saw that

Patient: Hello,I am 15 years old boy,and i recently saw that when i scratch,or do something with my legs,back,hands,face, or neck,it becomes red,appears very much little pimples,and after about 15-20 minutes it disappears and my skin is normal… What should I do,and what is to me?

Symptoms: When i scratch,or do something with my legs,back,hands,face, or neck,it becomes red,appears very much little pimples,and after about 15-20 minutes it disappears and my skin is normal…

Images:
Hello,I am 15 years old boy...-1 Hello,I am 15 years old boy...-1 Hello,I am 15 years old boy...-1

Doctor: