I don't know what to call it, but I've been calling it an allergy just to save from explaining. Physically I don't think I get rashes or swelling when I touch marijuana, but when I smoke a lot in a short amount of time I will start having ulcers form on my tongue. Very painful when they start to bleed.
Now I'm going to state this, I've smoked quite a bit in my life. Different suppliers, sometimes my own dealers, sometimes friends, different cities, sometime everyday for a week or so. Other than that I'm generally not habitual. I've done other things too, coke, shrooms, ex, etc... but for some weird reason nothing ever compares to what weed does to me.
Also I'm not an anxious person, nor am I a particularly stressed person.. but when I smoke, I actually go crazy. Doesn't matter how often I do it, could have smoked every day for the last 6 days before, its still the same. It's like a weird mental seizure causing all of my thoughts, sensations, and emotions to systematically fire. Sometimes I get to a point where I can't understand what people are saying, or whats going on. If I smoke too much I'll get actual seizures, or even appear as though I have catatonic schizophrenia, which includes involuntary motor disturbances, extreme emotional excitement, and bizarre flexible postures that depending on the high can be maintained for quite a long time.
Fortunately since being diagnosed with depersonalization disorder, some recently developed coping methods for it have strangely helped me to maintain a little bit more control when I'm high, and now when I limit myself to two puffs, I can ensure that physical seizures can be prevented. Despite only smoking a little however, most of what was mentioned above strangely will still occur.
So unless anyone can pin what this might actually be, I guess I'll still label it an allergy, although I do believe that the majority of the issue is probably neurological, and perhaps related to one of my mental conditions. Not related to marijuana usage, by psychological standards, I am actually considered mentally disabled, and can even claim it on legal and tax documents.