Dear friend,
It sounds like your boy may have a fever. You can wipe him down with a damp cool cloth - then immediately wrap him in a towel so he does not chill.
As long as he is still eating, he is not feeling that bad, however, you need to ascertain the cause of the fever. Because of his age, the first thing I am going to suspect is an abcessed tooth. Please carefully examine his mouth for any dental issues. If it is not that, you want to keep a sharp eye on him for a urinary tract infection. That would include straining in the litterbox or difficulty in uriation.
Other possible issues are liver, renal or pancreatic or even thyroid disfunction.
Observe him for the rest of the day and if he stops eating, developes a high fever, has any seizures or other serious symptoms you will have to have him seen by an ER vet ASAP.
Please keep in touch and let me know how he is and if you have any more questions. I wil be more than happy to help in any way possible.
Very sincerely,
Terri
Dedicated to Cats and the people who love them!
Please press ACCEPT if my answer was helpful and leave feedback Thank you! Terri