Im over it!!!!!

I just did something that i absolutely hate but im so sick of it

Ive warned him that I'd slap his nose, his face everything but what how can i stop my almost 9 year old

PICKING HIS NOSE AND EATING HIS SNOT



I just went to show him something on here, and after telling him already 4 times since he came home from school if I caught him again i;d slap his face he had his whole friggen fist up there!!

'slap' twice in a row cause he 'ahhhed' me when i did it the first time!

I am so over his behaviour atm...this is just plain disgusting and i honestly dont know why he does it.

What am I doing wrong? What can I do to make him stop???