What are some good physical therapy exercises for my knee? I hurt it as weightlifter.

Stretch and Strength. Stretching is always the first step. Hamstring, iliotibial band and gastrocs are all excellent to stretch initially. After that, the quadriceps is the ideal muscle to strengthen to stabilize the knee joint.
Evaluation. First of all, you need to find out what you "hurt" because this will dictate what types of physical therapy exercise will be good and also what would not be good for you to do when rehabbing from an injury. So the first step would be to either see a sports medicine specialist, orthopedist or a physiatrist to get a diagnosis and then help you with a rehabilitation plan. Hope that helps.