How to treat mouth sores?

Or "singaw" in Filipino language?

Because currently I have like three inside my mouth and it's annoying not to mention painful. I can't even properly chew my food. And I noticed that I've been getting these mouth sores too often. That made me typed in google search page "mouth sores causes and treatment".

And from what I read, here's what I suspect that causes mine.

1. Anxiety or stress
2. Iron, folic acid, or vitamin B12 deficiency
3. Changes in hormone levels

I know it's nothing serious and I'm sure it will  get better in time but I will still try these treatments just so I can be relieved and eat properly :)

1. I will avoid hot and spicy food
2. Will gargle warm water with salt
3. "Bactidol" might help or any antiseptic mouthwash
4. and oh..I should I avoid salty foods too.