Another major apthous ulcer on my tonsil?

I get these mainly when I get sick, run down, or have an allergic reaction. It's very painful this time because the ulcers position is right where my tongue moves. Everytime I swallow eat etc. It rubs it and it's excrusiating. I mouth breathe too so it exacerbates the situation. I've been using some chlorehexidine. As well as a saline solution, but it's causing me an incredible amount of pain. Any tips on how to relieve the pain? Drinking fluids hurts so much