H.H.
My son and daughter both get "blisters" of sorts on their lips when they eat foods that they are either allergic or intolerant of. I would definitely suggest seeing an allergist (maybe the one recommended below)... and a resource that has been extremely helpful to us has been the Dr. Sears "Baby Book". You can find that at any baby store or book store, and it has a lot of info on childhood sickness, how to bulls-eye food problems, suggestions for sleeping... bonding... tracking development, etc. Hope that's helpful!
Regards,
H.