Mouth Gel

Works Does Bonjela mouth gel buttons / acne?

I guess that would be because it contains alcohol which is a disinfectant?

You could try that, but I do not think so. Try using dettol antiseptic cream as soon as you feel them coming, it will not stop them, but they heal faster.
They are caused by hormones, and there is little or nothing you can do about it.
BTW, you use Colgate toothpaste? I found that the cause of my mouth ulcers and they stopped when I changed to another brand.