I Have a very big canker soar on the top of my lip. How do I get it off in 5 days?

For me getting cankers is common. I get them from eating any kind of citrus. About two days ago I noticed a very soar pain on my upper lip. I noticed a canker was just starting i have now had it for about three days today and it really hurts. So bad that i cant really talk without it hurting. I am going away for a trip in 5 days and i do not want a canker to spoil it. So if anybody know any at home remedy's or if there is a prouduct that will make it go away fast please tell me. I would really appreciate any answers that you give!!