Twisted knee, severe injury, difficulty walking, large dent below knee cap. Treatment?

I recently slipped getting out of my hot tub. The knee on the leg that was still in the hot tub twisted, and also took a hard hit. It has been a week and I struggle to walk. I can t straighten it, and at time there appears to be a large dent just below my kneecap. If I sit, it quickly locks and I struggle to get it straight enough to walk. It often feels like it is going to give out and has slightly done so a few time. I am sure it is just a sprain , but is pushing through the pain and forcing it to walk, etc. Better or resting it?