You need to keep it elevated and you need to keep it warm, this will help relax the muscle and alleviate any pain. You can take over the counter medication for the pain.
Use ice on area and elevate legs. A doctor may prescribe medicine to prevent swelling. Light exercise and light massage may also be advised by your physician.
I would get to a manual therapist that works with soft tissue injuries to first break up any residual scar tissue. Then work on lengthening the hamstring.
