I would recommend cleaning the area using an antiseptic skin cleanser with chlorhexidine. You can get it at most drug stores under a store generic or brand name like Hibiclens. You may already have some. It is useful to have in a human and/or animal first aid kit anyway. Great for kitty acne, hot spots, wounds, etc.

I would get some cotton gauze or something similar, wet it and add some of the Hibiclens. Then scrub the area in a circular motion vigorously to loosen up the hairs. You don't want the follicles to get ingrown and infected. Then rinse and pat dry. It'd be best if you could do this once a day until it dries up or you see a nice scab.

I would put the cone on her whenever you aren't watching her, which sounds like what you are planning. She may hate it, but it will really speed up healing time. I wouldn't bandage it at all.

Looks like everyone has diff product recs so far! LOL. I just based this on our clinic's hot spots protocol and my experience with Nipo's kitty acne.

Sue's idea about anal glands is something to consider too. Do you know if she had them expressed at the grooming place? Has she had the anal gland 'scoots' before?

Best wishes for your sweet Sam. Hope she feels better soon.