Best flexion exercises?

Hi I’m 3.5 weeks post op hamstring graft. I’m still not at 90 degrees flexion and wondering what exercises you found helpful to achieve more. I’m doing lying on my back and sliding my heel towards my bum (this one feels very hard and have a lot of tightness either side of the knee cap), lying on my front and pulling knee towards bum, standing and flexing the knee. I still have swelling so think this may be blocking things, I’m aware I’m reaching the 4 week mark and should be achieving 110 degrees to progress. Any advice would be great!