wrist hairline fracture on the ventral radius head

A couple of weeks ago i took a slip off a climb and landed on my outstretched hand, x-ray showed i had a small vertical  hairline fracture less than a cm long on the ventral side of my radius. The Dr just gave me a splint and said it should be fine in 4 weeks and he wouldn't need to see me again. I'm still experiencing a lot of pain if i try and flex my hand back and i have 60% or my normal range of motion. I'm using  ibuprofen and a topical anti inflammatory in addition to using heat, stretching and a metolius gripsaver. I can't really find any information about this form of injury online and i'm wondering what to expect for time of recovery and best practice for stretching and treatment. Do you have any information?