S.L.
Yes I would definately say this is a allergic reaction. My daughter who is now almost 4 at 2 years old had an reaction to a mosquito bite, both of her eyes swelled almost shut and the way you are describing the way her eye looked reminds me of what my daughters looked like at first. I would definately avoid food at has been cooked with shrimp or lobster or any food that may have been cross-contaminated with those, because I know you wouldn't want the reaction to be worse than it was intially!