Went to the hospital for sore throat on my left. Side and there were white spots. I was given antibiotics and a pain medication now it hurts worse.?

Go back. Go back to er or see ENT doctor if you can arrange it asap, you might have a peritonsilar abscess, especially if you have problem opening your mouth, and it can be dangerous as it can close your throat completely as it evolves, so do not wait if it is abscess it needs to be drained.