Hello and thank you for posting your medical question on E health forum.
From the history described, the lesions described on the leg seem to be erythema nodosum.
Erythema nodosum is an inflammatory disorder that is characterized by tender, red nodules under the skin.
These lesions can be seen in a variety of conditions including streptococcal infections , other bacterial and spirochetal infections, rheumatoid arthritis, sarcoidosis, drug reactions, etc.
The other systemic symtoms are nonspecific due to the associated inflammatory condition.
You might benefit by consulting your doctor or a rheumatologist for proper evaluation and diagnosis.
I hope this helps.