hello and welcome to HCM forum,
as you are aware that pericoronitis
is inflammation of soft tissue
that covers your erupting tooth, you should perform warm saline rinses 3-4 times a day. this will relief pain as well as resolve inflammation. you should visit your dentist
, he might place a medicated pack over the soft tissue, it usually takes a week to completely resolve, but depends from case to case.
your dentist will prescribe you antibiotics and anti-inflammatory medicine according to your condition, kindly keep doing rinses and keep that area clean off food debris.
i wish you good health.