Hypersensitivity of tooth

[asian12345]

I have a recurrent cavity at my mesial central incisor (front tooth), its a class III cavity. It hurts when i drink cold/hot water or food (like icecream), and it has sudden sharp pain when i use my finger nail to scratch it...I have done a restoration before for this cavity, but maybe the decay was not removed completely...And I have swollen lymph node at my neck, which is unilateral and its quite tender, it has last for 3-4 weeks until now, since my last restoration was done.
My question are:
(a) Can this recurrent cavity causes bacteria infection based on my symptoms?
(b) Is my swollen lymph node caused by this bacteria infection too?
Thanks a lot

[mommyofbhp]

Have the cavity filled asap. Have your physician look at the nodes. Yes, a bad tooth infection could cause the nodes, but you really need to be seen asap.

[scottma]

Seeing a dentist or physical is advised. Internet consultation will not solve your problem.