Right from the start, focus on rehabilitation of your hamstring as well as PREVENTION of further injury!! One of the annoying things about hamstring injuries is that they can come back to haunt you again, and again.

I agree with the comment below that you need to ICE++ over the first 48hours. Also though you can do some PAIN FREE active knee extension while sitting. ie: sit on the kitchen bench and slowly straighten your knee, lower and repeat. This should be pain free. Do this as soon as you've iced. Continue the knee extension for 5 minutes (pain free) and repeat the whole process (ie ice, then knee extensions) every hour.

This may be in contrast to what is mentioned below, but it is based on new clinical theories in to hamstring injury management.


After at least 48 hours (you may need to leave this next phase a little longer depending on how bad your tear is) you can move on to the stretch and strengthen phase.....the strengthening is vital as it will help prevent further injury.

Stretch:
Hamstrings and Quads and Hip flexors

Strengthening:
Hamstrings (concentric and eccentric)
Gluteals (butt muscles)
Adductor magnus

Get some massage on hamstring and gluteals
Check you don't have any restriction in movement in your lumbar spine.

If you need any further advice on which strengthening exercises fit in to the above description, I can be of further help!!

Hope this has helped so far.