Hello,
From the picture and symptoms it looks like Erythema nodosum. It results in reddish, painful, tender lumps most commonly located in the front of the legs below the knees.
Diagnosis is by physical examination and biopsy of the lesion.Other lab investigations like complete blood count, ESR,ASO titer, urinalysis, throat culture, intradermal tuberculin test, and chest x-ray may also be done.
I wuld recommend a physician/dermatologist’s evaluation.Treatment depends on the confirmation of diagnosis.Then Erythema multiforme has to be ruled out.
Hope it helps. Take care and pls do keep me posted on how you are doing or if you have any additional queries.Kind regards.
A bacterial eczema and you need antibiotics internally,do go to the ER and start treatment right away.