Can you become addicted to afrin (oxymetazoline)?

Possibly: I wouldn't necessarily use the word "addicted" when talking about afrin, but, as with any decongestant nasal spray such as afrin, you can get what is called rebound congestion if you use it for more than 2-3 days. This is a condition where the congestion actually gets worse, even while continuing to use the afrin, so you want to restrict use to 2-3 days only.