Go to urgent care or a Walgreens with medical services rather than an ER assuming you are not having extremely serious symptoms like fever or inability to move your jaw from intense pain. An ER visit is a fortune. Don’t you have a credit card? Charge it to the card.
Since everyone went ahead and told you how to get drugs through the back door I’ll go ahead and tell you Amoxicillin, Augmentin, Clindamyacin, and Flagyl are typically used for him infections, but you need the right dose, and it’s possible something like Amoxicillin alone may not work, but is often a first line drug given. Augmentin is Amoxicillin plus clauvanate, which makes it much broader spectrum. Those are penicillins. Clyndamycin is a different type of antibiotic, and Flagyl even another class of antibiotic, so in case you are allergic to something those are three different classes of drugs. Those names are American names, I don’t know where you are, and you can look them up for more info.
However, I do think your mouth should be checked by a professional. If there is an abscess taking antibiotics alone will not cute it. Your mouth is in your head, near your brain, and especially infections in the upper gums can be extremely serious, and even fatal. I am not kidding. See a doctor.
Disclaimer: I’m not a doctor.