Try putting some Shower to Shower (absorbant) powder on yourself where your holster will contact your skin. It reduces friction and heat and moisture.
(Or baby powder, but you'll get EXTRA points towards retaining your "man card" if you do that .... Baby powder works great, but has a side-effect of subliminally atracting women with the smell, and they can't figure out why they are attracted to you...

I use Shower to Shower powder because I can't run away from the wimmin as fast as I useta'.

This works great on any IWB having smooth leather or smooth horsehide or a smooth liner next to the skin, also works on all-kydex type holsters... I won't swear how well it works on any brand with rough side next to the skin, but I imagine it could help, I dunno cause I can't stand rough side on my skin, so I don't buy those brands any more, they occupy the "old holster box/drawer".