Red blotchy skin symptoms and conditions

After taking a 500mg Niaspan last night 1/2 hour after taking it I had this reaction: Hot flush in my upper body, face,neck and arms.
Happened out of the blue. got scared.
Went to the bathroom and washed my face with cold water.
Came over to the iMac (computer) Googled Niaspan allergic reactions, found this site and was mentally relieved to note that this was a common side effect of this drug.
Consumed 10 oz of water calmed down and fell better within 6 or 7 minutes.
While some people curse the amount of info on the net I am not one of them.
I am really glad that people share info like I am doing.
I suggest though if any of the side effects are worse then mine yo go to the ER and if you cant hit 911.

I had a skin infection on my lower legs and was prescribed Cephalexin Monohydrate. I took it for 6 days, 4x per day, then stopped. I was supposed to continue on 2x per day for the next week.
I started itching at the top half of my buttocks and it quickly spread all over my back, chest, shoulders, arms and onto my scalp. Small lumps or hives and red blotchy skin nearly all over my old body. The itching was driving me crazy. I didn't know where to scratch or rub next.
My doctor couldn't see me for another week so I went to see another doctor who prescribed Phenergan (promethazine hydrochloride) tablets and Celestone M (betamethasone) cream.
Relief came within 24 hrs, I went through 4 days of hell and while still itchy on the 5th day, it was getting better. I also used ionil T ( a medicated shampoo ) for my scalp.
I have never been allergic to any drugs before this monster
This antibiotic should come with a warning

Severe depression,personality change, suicidal thoughts, panic attacks. Acne on face and body, hair growth on face, red,blotchy skin, bloated face. Hair loss on head. Constant hunger, sugar and caffeine cravings. Constant feeling of cold, even in warm environment. Frequent urination, dry eyes and mouth. Greasy hair and skin. Muscle and joint pains. Raised blood pressure. All these symptoms began when I started taking Yasmin and have cleared up since I stopped taking it. Never again!