Ambien and hives

has anyone ever had sudden case of Hives on their face? from taking 10mg. of Ambien for 4 weeks. Sometimes, I even just took half that. I have never had Hives from Anything before in my life......not lotions, foods, soaps, sunbathing, pools, hot tubs, medicines, back patches, prescriptions, vitamins, etc. never. I'm in my 50's. Had this four days now and after a shower seems worse. Active Ingredient in Benadryl/Sominex seems to make it a little better, but can't take that and be sleepy all day/all evening. Taking Ambien is one of only 2 new things I have done differently in the last month.

I have been taking ambien on and off for two years on the advise of my doctor (neuroligist) Ever since I had lower back surgery I have developed this irritable and shaky leg syndrome, which causes me not to sleep. I have been taking all kinds of pain medicine, which i seem to have alergic reactions to most (Hives, upset stomach etc.)
The only thing that has helped me sleep is Ambien. However, I have noticed that after I eat, my stomach really hurts and i get heavy palputations (In the stomach area).
About 6 weeks ago I was rushed to emergency beacause of stomach pain, bowel movement was black ( thought I had a bleeding ulcer) But they found nothing.
Could this be the side affects of Ambien?