I've heard people saying "Excuse me" after sneezing in public, but should it be "[I am] sorry" instead?
An answer to Difference between “Excuse me” and “Sorry” says that:
"Excuse me" is asking for permission. "Sorry" is asking for forgiveness.
So, if you want somebody's pen, you will ask like:
Excuse me, can I borrow your pen?
And, if you found a pen but you didn't find its owner and, due to your emergency, you used it and later explained it to its owner like:
Sorry, I had to use your pen in your absence. It was an emergency, sorry again.
So, following the above concept, saying Excuse me after sneezing will be like doing something first and asking permission for it later. What is wrong with saying Sorry here instead?