Remove the allen screw completely and let us know if its still stuck. Can you wiggle it?

Hi Tom...

Try what Ballengerb1 suggested first... may work.

Otherwise, for most of these, you would normally just remove the CAP at the very tip of the handle? If you "pop" the cap off it should reveal a screw that simply unscrews to remove the handle and anti.-scald parts.

Let me know what you think... OK?

Mark

I can't remove the Allen Screw . It looks like someone before made it dull. :(

How can it unscrew this screw out??

The screw is likely too small to drill it with an Easyout but you could try. Easyout kit is about $12 at most box stores or automotive shops