Please help. Blood in the back of throat.

[Emiliolopez12]

Hi, brief introduction; 1-2 weeks ago I developed swollen tonsils with no other symptoms but sore throat, swollen lymph nodes in the neck and basically that was about it. Last week I visited the otolaryngologist and he said it didn`t looked that bad, so he gave me a shot of betamethasone and I've been on clarithromycin for about a week with not much of improvement. Like 3-4 days ago, I've developed White spots in the tonsils and blood mixed with mucus down the back of my throat. Should I be worried? How long will this last? Is it outliving antibiotics? please help I'm really worried