Ah poor girl.
Pongo used to get hotspots quite regularly. Like you, the first time it happened we didn't notice until it had developed into something quite nasty (photo below, poor puppy!). As other people have said: use very very VERY high value treats to distract while you keep it as clean as you can with hibiscrub, and yes try to get a bit of hair clipped off. Then dry it very, very thoroughly. Keep it really dry. The pills will work eventually - ointment would be faster and better, but the pills will work.
By the way, I'd suggest using hibiscrub very much diluted, not neat. The skin on the hotspot is really sensitive and I think hibiscrub can be powerful stuff.
Once it is gone, you just need to be vigilant about not letting damp warm areas fester, especially in those bits of skin that are folded and don't get air (with Pongo it is the fur round his neck, he has a thick ruff of fur). Dry those bits well after swimming, for example.
We have also found that adding good quality salmon oil to Pongo's meals has pretty much completely got rid of all hotspot trouble (and his fur is glorious). We get a big bottle from csjk9.co.uk and it lasts for ages. I'm not saying that would work for you as well as it does for us, but it has been a bit of a miracle cure for Pongo.
Good luck....it is miserable watching them in pain and fear but it will pass and she won't remember anything about it. Just get her through the bad bit.