Thanks for posting your query.
The lump needs evaluation by a clinician by local physical examination.
The lump is likely to be an avulsed head of quadriceps muscle of the front thigh or it may be a torn muscle belly or an organized hematoma
self treatment is not recommended because it will increase the deformity
and may damage the muscle permanently.
Mostly such problems are corrected by repairing the torn or suturing the avulsed end back to the natural site.
Mostly the deformity is corrected fully with function restoration.
Hope I have answered your query.
If you have any questions I will be happy to answer.
Wish you a good health.