26 month old face picking, any advice?

[mummyinthemiddle]

My 26 week old DD had a small graze on her face a couple of months ago. She will not stop picking it and now it looks like red and angry and I am worried she is going to make it scar. She is sleeping in long socks as mittens and this helped for a while but now she picks it in the day time. If I catch her I tell her stop, and she does but still this thing just won't heal, it will get to the stage where it is nearly better and then she starts it again.

Does anyone have any advice on how I can get her to leave it alone, or advice on anything I can put on it to speed up healing?

I saw something like this on Supernanny. They gave the child a soft make up brush to rub on her cheeks instead and praised her every time she did it. They ignored any negative behaviour as far as possible, too, I think.
For the scarring, buy vitamin e capsules and break them open with a pin, then squeeze it on twice a day. Bio oil could also wrk.