A cold sore like lump appeared on my lip on the 28th, I've suffered with cold sores forever but haven't actually had one for the past two years. This ulcer appeared very fast and formed a full scab over night which has completely come off whole today. The sore is now bright Red underneath and tingling constantly. 
Does this sound like a cold sore or something maybe more sinister. 
I really hope this makes sense to somebody o would have added a photo but I don't know how. 
thank you for taking the time to read this post.