Hi,
The lump underneath the tooth with a cavity maybe a periapical abcess, ie: pus formation, forming a lump due to infection in the tooth. This needs to be treated along with your other cavities. The abcess suggests that the tooth in question is already dead which needs a root canal treatment to drain the pus, along with a course of antibiotics to eliminate infection. once the pus is drained the lump will resolve immediately.
The dental offices are very patient friendly now a days and you should not worry at all. In today's day and age the dental treatment is almost painless in most of the cases. If you are still worried just go for a basic checkup on your first visit and start the treatment in your later visits once you get familiar with the doctor and the clinic.
Regards

Hi,
Thank you for the query.
As you said you have cavities in your teeth that might be the reason for the formation of lump in the gum. I mean infection in the teeth leading to formation of abscess which is had lead to swelling in the gum.
Yes, it has to be treated as early as possible. I advise you to see your dentist get an x- ray done and rule out the exact cause for it.
Treatment could be rootcanal therapy followed by a course of antibiotic and analgesics if it is due to infected teeth and if it is gingival abscess then it has to be removed and a course of antibiotic and analgesics should be followed .
Hope this information helps you.

Lump on gums can be because of canker sores or it can be because of gum abscess. Infected tooth can also lead to pus drain on gums. If it is a canker sore, then it will heal in 10-14 days on its own. Canker sores are self limiting. If it is paining, then orajel can be applied over it and you can continue with warm saline rinses to avoid any secondary infections. Gum abscess can occur because of some sharp food stuff impinging on gums or because of impaction of some foreign object. For treatment of gum abscess, cause of gum abscess is removed and drainage can be established by warm saline rinses. Dental cleaning or curettage may also be required. If lump on gums is because of infected tooth, then root canal treatment of infected tooth is required. If it persists beyond 2 weeks, then visit your dentist for evaluation. By that time, continue with warm saline rinses.

dear friend,
thanx for sharing your concern,

you have mentioned about cavities in your teeth that might be the reason for the formation of lump in the gum.

infection in the teeth leading to formation of abscess which has led to swelling in the gum.

Yes, it has to be treated as early as possible. I advise you to see your dentist get an x- ray done.

Treatment could be rootcanal therapy followed by a course of antibiotic and analgesics if it is due to infected teeth.

if it is gingival abscess then it has to be removed and a course of antibiotic and analgesics should be prescribed.

If you are worried just go for a checkup in your first visit and then treatment in your later visits.
need not worry dental treatment is almost painless nowadays.

hope this helps.
thanx.

Hi, please do visit a dentist. There is nothing to feel scared about it. The more you delay, the worse your oral health will get. You have got many cavities and the swelling that you are referring to is a periapical abscess due to the badly decayed and infected tooth. Please go for a root canal treatment for the tooth and go for restorations for other decayed teeth. Hope this helps you. Take care!