Your daughter might be having a skin condition known as erythema nodosum
. In most of the cases underlying cause is not known, however it may occur in association with infections, drug intake, pregnancy
etc.It manifests as painful lumps underneath the skin that bruise and later on disappear in few weeks time. These may be associated with fever, weakness joint pains
etc. The treatment involves course of steroids along with oral antiinflammatory drugs.
The case is usually diagnosed by a dermatologist
or a physician alike. You may consult a doctor specialising in dermatology or medicine or a rheumatologist
for the same.
Hope that answers your query. Take care.