###Human: Noticed redness, swelling and pain in the arm after popping a blister in a Meth addict. What to do? ###Assistant: Hello. This looks like a cellulitis (attachment removed to protect patient identity), it is an infection of subcutaneous tissue. He needs antibiotics and blood test. Convince him for visit. He will need a hemogram test, and blood culture to look for the extent of infection. In treatment, he will need antibiotics like Amoxicillin Clavulanate combination 625 mg three times a day along with some antacid like Pantoprazole 40 mg once a day. For pain and swelling, you can continue Ibuprofen, you can use Magsulf ointment for local application for swelling. He will need higher antibiotics as it appears severe cellulitis. So my advice is to visit ER soon.