Did you take them out and very that the passage is clear? Blow through them. You should be able to see light through them if you hold up to the light. Hopefully there's nothing wrong with your lifter. Also, I suggest that you check to make sure that they are straight.
If you wait till the nut backs off before fixing it, it may get to a point where that valve is no longer opening or functioning properly. That makes for a very rough engine.