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Nodules,rashes andopen sores may be due to infection particularly in view of exposure to suspicious material but that is not the only probability in such scenarios. It may be a manifestation of some systemic inflammatory conditions like Systemic lupus
erythematosis, Rheumatoid arthritis
, Rheumatic fever
, connective tisue disorder to name a few.
You should get evaluated by a physician of your locality and after physical examination he will conclude the necessary work-up for you.
Please get these investigations and if you like, inform me in a Fresh Query / Follow up Query for further fine tuned opinion
Wish you a great health!