Acidophilus probiotic...what if you DON'T "refrigerate after opening"?

I have been using a brand from a local drug store that has each pill in one of those individual blister things where you pop it out the back when you're ready to take it.  Well, I saw a post on this board about a big sale from Puritan's Pride, so I bought 3 bottles.  I opened one and have been taking it daily for about a month.  Last night I was looking at the bottle and in tiny little letters at the very bottom it says refrigerate after opening.  Obviously I think if this is important it should be written more prominently on the bottle, but anyway, what now?  Can this "go bad"?  Should I throw that bottle out? 

Live bacteria. They die.  so the qty iin each capsule is less.  But they are still OK.
i.e. lists 5 Bilions - after 1 month - some will die so yu may get 4 or 3 or 1 bilion.

Good to know.  Thanks.  I just got home from work and put the bottle in the fridge.