WWYD - rubbing mane

[Leam_Carrie]

I'm a bit of a horse owning novice and not sure what I should be doing. I was grooming my horse earlier this week and found that she had rubbed the whorl under her mane (might have been bitten as there's lots of mutual grooming going on with the other horses). I put on wound powder, used fly spray round it to keep it off, have tried hibi scrub to clear it and then sudo cream to act as a barrier. She's clearly rubbing it, as I found mane on the fence posts, so it must be sore. I've only had her a few weeks so have a rather limited first aid kit, but can go and buy anything she needs (currently have wound powder, hibi scrub, savlon, sudocrem, purple spray and then various other bits like poultices). Any suggestions?

I'm going to have a try at uploading photos... (sorry if they are massive)

And one of her - just as I think she's gorgeous! (I am working on her weight)