Hi

At first do sort out immflamation and fluid use cold, compression, elevation.
alongside start doing gantle stretching of hamstrings, ilotibial band, calf muscles.
pain free exercises for quads ( isometrics) calf, hamstring, pelvic/hip muscles ( range of motion exercises gradually adding resiasstance. slowly implemment non-resistive exercises - knee flexion ( in range of 10-30 degrees ) and gradually increase it.
Massage
the most important seek advice from a specialist ( physio, sport practitioner) etc

all the best