You can stop it from happening again by not slipping again?
When you say slip, do you mean fall or slip and something pulled? If you fell, my guess is a hip pointer.
Accelerated Mobility Physical Therapy
If you slipped and pulled something, you'd need to describe the motion better and what makes it hurt.
That all said, if you can, see a sports doctor or whomever is in charge of these things because I'm not a doctor.