If the pills also contained acetaminophen/APAP (Tylenol) which they likely did along with binders and fillers it just clogs your nasal passages and prevents much of the codeine from being absorbed. It all drips into your stomach or stays in your nose until you blow it out.
Pills were meant to be swallowed and in this way your only dangers are overdose (which depending on the dosage would require several pills) and opiate addiction (codeine is an opiate)...but that would take repeated use for about a week.
Acetaminophen can cause liver damage at high doses but you would only need to worry about that if you planned on taking a number of pills where the total APAP content would be over 3000mg. Some people will exaggerate the risk of liver damage while others will ignore it so lets just say 3000mg at once isn't the best idea considering that it wont contribute to your codeine buzz anyways.