Sorry about your problem! I'm about in your age group. Is your mp particularily worn in an area your lips touch? Metal allergies are not unknown. Maybe some web research in order. I found a cheap product you might want to get to test the MP problem using your own. It is a Runyon brass instrument lip saver. "soft plastic material slips over the rim of trumpet, cornet and flugelhorn mouthpieces cushioning the rim an providing cold weather comfort." .
Interstate Music Item BA328. Price $5.39 plus shipping. Says only 6 left in stock. That might isolate your lips from metal and you can see if their is any difference in your symptoms. Good Luck!
