Mouth Ulcers More Condition_symptoms What Is The Reason For Me Having Four Different Mouth Ulcers?

What is the reason for me having four different mouth ulcers? - mouth ulcers more condition_symptoms

I am a man of 19 years and a few days ago I realized that I had sores in the mouth and they're not running, I can not eat because it hurts, and I've tried everything and mothwash it, but to work to swim, I also pain on my tongue, I smoke, but only once a week, and socially. Besides the fact that I take care of me eating itself, well, drink well,

I wonder, could it be something serious like cancer in the mouth?