Hello and hope you are doing well.
Your symptoms could be due to a fungal infection. Most common cause for white patches is candidiaisis. It is usually caused by candida albicnas, which is a fungal infection. The white patches have a cottage cheese appearance. They can occur as a consequence to throat infection or sometimes steroid inhalers are known to promote their growth. You need to consult a doctor for proper assessment. In the meantime you can try warm salt water gargles and betadine mouth washes.
Hope this helped and do keep us posted.
have you eaten something that is hot or tastes hot (pepper or something like that)?? I have had that once or twice and it went away. If it has not in a few days, I would call the doctor and see if you need to come in.