At what point should I have a bump on my neck checked for staph?

Good question. If it doesn't get better using topical antibiotics within a week or two. .
Maybe staph. A bump on the side of you neck may be an enlarged lymph node; if the bump is filled with pus , it can be a pustule, foruncle, most of these lesions are caused by staph aureus, but other bacteria must be ruled out if the bump persist. Some staphs are resistent to methicillin (MRSA) and can cause serious infections, a culture of the pus form the bump may be obtained to determine if it is mrsa.