GLOVES: Firstly, I don't use gloves or any grip product for spins. Despite sweaty hands, I can barely get enough momentum (overgrip) with bare hands, let alone with grip aids! I heard recently that gloves don't allow your hands to strengthen as much as using bare hands. Perhaps, your grip can be more relaxed in gloves as they grip for you? I'm weaning off them so I don't end up at a loss if I for some reason don't have gloves when I pole and I don't want to lose any ounce of potential strengthening. I'll use them as a last resort or a new scary move backup.
PAIN: I make sure I am really motivated and can be distracted by getting into the music, having an audience (in class, or my camera) and focusing on my form...and I somehow vacate the area of my brain that focuses on the skin pain. I feel it, but I just don't care. 'Yeah, this hurts a bit, but I rock this!'
The lessening of pain, I think anyway, happens over time as you get used to it and as your muscles and form develop to better execute the move (as others have said). If you do now exactly what your started out doing, I reckon it would still hurt the same.
I'm not a believer in physical desensitisation. Yes, I am slowly building small, thin callouses on my hands (after 1 year of dedicated poling and recently starting assorted aerials apparatus), but I still blister over and under them. Plus, I still bruise a crapload (more than anyone else I know who's not anemic or has clotting issues), even doing a move very well and having done it several times a week for a year. My diet is good and nothing else bruises me like pole contact. A strong fall on my shoulder, a torn hamstring, a bad sprained ankle, a high speed run in with a table, smashed in the head so hard I see stars with a play tea tray... no bruises.
However, I love every pole bruise and ache because I know where it came from and enjoyed getting it!