What kind of therapy can I do for my knee?

To heal faster... hmm. Ask your doctor.

However, a common problem with knees is that the muscles on the two sides of the kneecap can become unbalanced in strength. This causes your knee to ache when walking. You could figure out which side is weaker, and do an exercise which strengthens just that side. But it's easier to simply exercise both sides.

What you do is lie on your side, raise the leg in the air a few inches, so it isn't touching anything. Then raise your knee towards your chest, and slowly scissor kick it straight. Repeat this for a minute. Then roll over to your other side and repeat. Note that this leg will be on the bottom for one of the sides. It's harder to keep it in the air on this side. Just do it. It's only a minute. There's no real reason to not do this for the other leg. It's only another two minutes.