Right tonsil quite large. left tonsil not visible. clear asymmetry. what could this be? throat feels scratchy

Common: The tonsils are a first line of defense against infection or irritation. They are commonly enlarged and often not symmetric. If you have a scratchy throat, it may be you are early in a respiratory infection., most often viral. Now asymmetry with severe pain, fever, trouble swallowing, etc can be a sign of an abscess, a complication of some throat infections.

Infection: The one sided enlarged tonsil is concerning. I would get this evaluated today. Do you have a fever? Do you feel sick? This often is a local infection that would need antibiotic treatment and proper follow up care. In worsening cases this could be an abscess and need draining. Good luck!