I accidentally swallowed a small plastic ring (approx 1.5cm in diameter) i can feel a lump in my throat and there is no pain and i can breathe, swallow, drink and eat. do i need to be worried? eating didn't make the lump feeling go away?

See your doctor : Won’t discuss why it was in your mouth. Most plastic is not readily visible on X-ray. An ENT doctor can look inside and see it if it is still visible.

Foreign body throat: You need to go to the emergency room for this. An endoscopic exam is needed. The most serious risk is that a foreign body can move into the trachea and cause airway obstruction.