I was wondering what reaction metrogel would cause and could it cause steven johnson syndrome or dizziness ?

None of those: Metronidazole gel, somewhat useful for control of rosacea, will not cause dizziness. If you have Stevens Johnson syndrome it is a SERIOUS condition often caused by a sensitivity to a sulfonamide or other medication. In my area it is a favorite diagnosis by ER physicians who seldom get it right. A topical med is extremely unlikely to cause anything like this.