I have had a sore spot on my gum right under my lower front teeth. i thought i injured it when brushing my teeth in a hurry. i it has not gone away and its been a week so i looked and i have a small oblong open lesion on my gum that is painful. i also

Is : Is this the only lesion, or do you have any others? It could be an aphthous ulcer, which may have formed from the toothbrush trauma. They usually last a week to ten days. A differential diagnosis of a lesion, over the internet, sight unseen, is not prudent. Your best bet is to go to your dentist or an oral surgeon to have them take a look to be absolutely sure.

Go : Go see the dentist , this is much better than worrying & wondering about it. He'd be able to tell you right away....Maybe you haven't been seen in awhile & you just need your teeth cleaned. That would be nice to do anyway since you just quit smoking. The sore in the front sounds like an ulcer because it hurts & they are self limiting & resolve on their own in 10 - 14 days, but go have an exam & then you'll know everything about your mouth in just a few minutes.