Over the counter nasal sprays (Afrin) do clear your congestion almost instantly but you are more prone to rebound congestion and therefore that is why most over the counter nasal sprays become addictive. I have known multiple people that used the OTC nasal sprays and they became addicted (one of them was my mother).

If you have continuous problems with congestion I suggest that you talk to your doctor and get a prescription spray. I am lucky enough that my doctor always has plenty of samples. I hope this helps.