About four months ago I messed up both my inner hamstrings really badly. I was overzealous trying to stretch out my outer hamstrings during a sprint workout (I'm a distance runner, but decided - stupidly - to work out with the sprinters for a day) doing 30s, 60s, 80s, and 100s, and tore both the inners. I had trouble walking for a few weeks and didn't even bother trying to run for over two months.
I've been trying to get back to running, but every time I push the pace a little bit, I'm in serious pain the next day.
There's an obvious enough knot in my hamstrings if you try and massage them, so I'm thinking I may have caused a minor rupture in one (or both of them) when the injury occurred.
In any case, what can I do to strengthen and help my hamstrings recover?