What is a desensitizing agent? I had a large filling removed from a molar & re-filled & now it is so sensitive, even tap water feels like fire.
– Shirley from Texas
From the description you give of the intensity of your pain, it sounds like the tooth that was filled is infected and will need a root canal treatment and then later a dental crown.
Here are some guidelines to see if you need your dentist to help you with this pain:
If the tooth is getting more hypersensitive with each passing day, it is probably infected. If it is gradually getting better, it will probably recover.
If your tooth is momentarily sensitive from cold water, but it’s only for a couple of seconds, and as soon as the tooth warms up it feels fine, then it will probably recover. If the pain lingers more than a few seconds, it is infected and will need a root canal treatment.
If the tooth begins hurting spontaneously, where you get a sharp pain without any cold stimulus, it is infected, and will need a root canal treatment.
If the tooth gives you a sharp pain and then all of a sudden the pain goes away, cold doesn’t bother the tooth any more at all, the tooth is probably infected and needs a root canal treatment. What has probably happened is the tissue inside the tooth has died, which takes care of the pain, but now the infection begins spreading out the end of the root of the tooth and into your bone, causing an abscess. That needs to be fixed.
I hope this is helpful.