Hi there ~
I understand your concerns. However with the description of your lesions, and the limited information and without examination it is not possible to come to a diagnosis on an online forum. However I appreciate you asking the question and I do not believe that the lesions in your leg and arm are necessarily linked although they may be due to the same disease process. I hope you continue to keep good hygiene, while you set up an appointment with a dermatologist
to get answers to your question. I hope this helps.
Take care and have a lovely day!