Canker sore and braces!?

ok so i just got braces (this is my 4th day) and on my 2nd day i developed this canker sore thats way back by my molars and behind my teeth not in front so it kinda hard to see, and it hurts soo much! i also have like a bar from my braces that goes accross the roof of my mouth and on the left side there is like a bump and it looks like the bar might be too tight over there? anyways does anyone have and home remedies i have tried baking soda and now i am goin to try some salt (ouch thats gonna hurt) thanks for answering!