The best way to treat a pus filled lump in my mouth on right cheek@ home? plus salivary glands are red, and swollen under tongue. what is it & is it an emergency?

Oral mass: If you have a large mass filled with puss in your mouth, I would get seen promptly. You might have an abscess .

Yes: Any infection is an emergency as the infection spreads through your blood stream to other organs. Best way to treat it? See a Dentist. You don't have the training or experience to threat this, let alone properly diagnose it. You need about another 10 years of schooling to reach that level. See a Dentist NOW.