you need to have you leg examined first -- not something that can be done over the internet. if you do need treatment like an antibiotic this would need to be prescribed by a medical provider -- other thing that cannot be done on line.
i had infection in left upper leg if antibiotics were needed. no idea where in fection came from. i have hardware in leg from surgery seven years ago could this cause it? have difficult being on it for long time and trouble walking.