You may be able to find a better Community than this one for discussions on skin issues, including scars.
Allergies are very difficult to diagnose, even for a doctor trained in the field and who has hands on experience with you.
If there is a chance, good chance, that your problem is food based, I'd try a vegetarian diet for a few days/weeks to see if that helps. If it does you can then start to add back other food items one at a time to see what else you can eat. Of course if you have an allergy to one or more vegetables.. this approach would not work.
Here I assume cutting out sea food and chicken helped, at least for a while.
There are other limited diet approaches you may what to research. The method that seems to work (the best?) is to make a diet very limited and boring (hard to do) and see if one gets better, if not, switch to a different limited diet, and so on. It takes time and sadly it sounds like more scars - so that is a good subject to study on its own. Maybe dermatology community, I assume there is one here on MedHelp, I didn't check.
What if you are allergic to the antibiotics (like penicillin!) or sulfites being used to preserve meats and seafood? Have your allergist test you for these allergens. Also try eating organic meats and seafood this may lead you to a clearer understanding if you are allergic to the foods or the chemicals being used in them. Be safe though, don't give yourself a severe reaction when you are testing out foods eat a bit and see how you feel. If you feel fine after a day you should be okay to eat more. Check out this page for more information:
You may want to consider ALCAT testing for food, chemical and antibiotic sensitivities check out this site, its costly but worth it if you're desperate for answers and relief:
When you heal your body from the inside out your lesions will heal as well. I would find the source then look to healing them, your body is telling you something you just have to really figure out what it is.
I'm not a doctor or allergist, maybe when I finish college, we'll see. Hope you feel better.