Due to trauma,blood might have collected in the thigh.It is called haematoma
.It will be resolved spontaneously in course of time.Due to the changes in the collected blood,the colour purple/blue is een.
Please take an Anti inflammatory drug twice daily.
If it is not resolving ,consult your surgeon and proceed accordingly.
If the surrounding area is red,add an antibiotic to combat the infection.
Nothing to worry
Wish you speedy recovery