Infection of tooth beneath crown

There is no need to cover the tooth. You can continue using your antibiotic. You should consult with a different endodontist.

If your crown fell off and there's swelling near the root (a hard bump), it's likely there's an infection or an issue with the root of the tooth, which is why you’ve been referred to an endodontist. The amoxicillin will help manage the infection temporarily, but it won’t fix the root problem.
Should You Reattach the Crown?It’s best NOT to reattach the crown on your own. Covering the tooth could trap bacteria, worsen the infection, and make the situation more complicated. Instead, keep the tooth clean and exposed until your endodontist appointment. Use a temporary crown cement (available at most pharmacies) only if absolutely necessary for cosmetic reasons, but avoid chewing on that side.
What You Can Do:-Keep the Area Clean: Rinse with warm salt water or an antibacterial mouthwash to reduce bacteria and swelling.-Temporary Protection: If the tooth feels sensitive, you can use dental wax or a temporary filling material to protect it.-Monitor for Pain: If the swelling worsens or you develop severe pain, contact your dentist or endodontist for an emergency appointment.
While waiting for your endodontist, focus on controlling the infection and keeping the area clean. Your endodontist will assess the tooth and likely recommend a root canal or other treatment to save it. Avoid reattaching the crown yourself unless advised by your dentist.