Are my lips allergic to something or is it just my head?

The thing is, allergic reaction would include swelling, itching, hives. An irritant reaction would include burning, redness, discomfort. Eczema would probably be a chronic condition of the lips that you would have to treat on an ongoing basis. I would say that since all these incidents happened in conjunction with foods that you have had an allergic vs irritant skin reaction to the food or ingredient. It may be that you just have sensitive or allergic prone lips, especially with a history of eczema on your hands. And if you do have eczema on the lips, then that eczema would easily get irritated with spicy/hot/acidic foods. The mango/strawberries probably have a certain amount of citric acid in them which may burn the lips, even though the rest of you is okay. So, I think that limiting these foods and avoid touching them to your lips would be the best thing. However, if it continues to be a problem or gets worse, you should check with a dermatologist who can give you medication for treating your lips. Aquaphor Healing Ointment is also very good product to coat and moisturize your lips with.