Hi..
Can understand your concern..
As per your complain when the tooth gets deeply decayed due to infection caused by bacteria, there is formation of pus near the root tips of infected tooth and is known as a "DENTAL ABSCESS" and it creates pressure when there is no escape way and causes pain.
The formation of pimple is a pus filled lesion caused due to infected tooth..
Taking antibiotics and painkillers can help in reducing the infection but it takes time for the infection to reduce to an optimum level so that the pus dries down BUT one thing you should understand that at times only medicine cannot help as the source of infection that is the infected tooth is not removed and act as persisting cause of flaring up of infection.
There is no specific food stuffs that you can take or avoid to reduce pain or protect the tooth if it is already so deeply infected. The only precaution which you can take is avoid hard food items and do not chew from the affected side to prevent flaring up of pain.
You should also avoid very
cold and very hot drinks so as to prevent pain..
Avoid eating sticky foods as they can lodge in the infected tooth cavity and can be painful while removing..
Just continue taking the medicines on time and mostly after a course of 3 or 5 days the
dentist will perform the extraction of the tooth as hopefully the infection will considerably reduce even if you still see the pimple.
Hope your query is solved..
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Thanks and regards..
Dr.Honey Nandwani Arora.