I hurt my hand in gymnastics and my hand hurts under my pinky it hurts to move and to touch and to make a fist. what did i do to it?

Get an X-ray: Make sure you didn't break a bone. You should get an x-ray of the hand. Meanwhile, ice and tape the small and ring fingers together.

Possible fracture: Hand fractures usually present with a traumatic event followed by pain with motion and palpation. Discontinue gymnastics until you get some proper x-rays by a hand surgeon to see if there is a fracture. Severe ligament strains/sprains/tears can mimic fractures as well.