This has nothing to do with syphilis. Syphilis canker doesn't show that soon. No STD does. You did not have a risk.
If it is syphilis then the lip will get better and you will forget about it but it is still in your system and will break out again but stronger and on other parts of your body. Then it is more difficult to treat. So do go to the Doctor whilst it is not serious. All the best.
You should see a doctor, you don't want to wait to see if it gets better, it could be something more serious.
I think you should go to the docs to really find out wat it is instead of waitin cause then it might get worse, I don't think ur overacting bcuz it seems like it came right after u did wat u did..so go to the docs
Check out with your Doctor for Syphilis. That starts with a red swollen lump on the lip. Luckily I think a course of penicillin does the trick of ridding you of this for good.