I used vicks baby vapor rub on my 2 month old chest, then realized the box said 3 months! will he be okay? i used a very little.

Yes: He will be ok. When i recommend, I usually say to put a small amount on the clothes or onesie, not on the skin itself.

Very safe: if there was a reason to use the Vicks such as a lot of congestion then fine Sometimes parents hear a little congested breathing and are concerned If it doesn't bother the baby then don't it bother you

Safe but worthless: The primary reason for congestion in infants is small nasal passages that swell in response to irritants, like the fumes put off by Vicks/hairspray/smoke/dust/perfume/etc. I never advise it below school age. It may be safe but I find it aggravates the problem in young infants.A good nasal wash out with saline and removing airborne irritants works better.