Ok - I'm a bit late to this party but I'll weigh in too
You've most likely got mites or lice and you won't get any problems with these passing onto you or your family. They live on pigs. You'll feel itchy because you're thinking about critters and sometimes people are a little sensitive to hay generally without actually being allergic so you can brush hay off you and think, "Oh no! I'm itchy!" but it's not mites - I'd have been eaten to the bone by now if it was! Never had a bite yet - and trust me, I'm delicious
EACH PIG needs treating 3 times two weeks apart as Piggies&Buns said above. When I had 4 it felt pricey! How many do you have? I've only ever had adults so only ever used the xeno-450. I box=6 pipettes= 3treatments for two piggies. About £25 per box so it was just over £50 to treat 4. Not every pig in the past has been 1.2 kilo but they've been no smaller than 1 kilo. I also tried to count drops - failed - panicked about overdosing and actually there was no problems. But a more reliable way we found was is to get a 1ml syringe and suck up a pipette and work from there with the maths. So full pipette for 1.2kilo and if piggy was only 1 kilo she should have had 5/6ths of that... she wriggled, I splurged, she got the lot but it ended up fine - no ill effects, as did the fatter one who freaked at the last minute and I bet I had half of it up my arm and was trying to scrape it off and rub it back onto her. Wash hands well after treating!
Ivermectin soaks into the skin and goes round the piggy system so it'll be merrily killing critters for a few days after and then slowly starts to wear off. I treat mine and 'blitz' the cages a day or so after treatment. I actually don't use F10 (although it
is a good investment) as we have the plastic tray type of cage but they get HOT showered and scrubbed out with white vinegar (to dissolve the crusty pee bits). I wash fleeces at 40 - we have two sets so I reckon that after washing, drying and sitting around not near any pigs for 5ish days anything that might have survived on there would have died off without it's regular piggy meal. I bin the cardboard and sometimes put stuff in the freezer for a few days if I'm attached to it (which is how we deal with clothes moths too!) but any wooden houses etc have in the past been relegated to the garden or put out of the way for a month or so. You could try putting wooden things in the oven at min 60degC for a few hours - don't go over 100 - but obvs not fleeces which will melt! Any cotton stuff (we have one or two mats) could also be hot washed or tumbled after. We tend not to have wood in the enclosure now - I just cut cardboard boxes into interesting shapes. I don't clean the cages any more often between treatments - anything that hatches out can just die the next time round.
In theory two treatments
could sort it but the third is a belt and braces - and cheaper than having to repeat the whole fandango a few months later!
I don't cut hair for mites or lice. They need to feed off the piggy skin anyway so you'd have to pretty much shave 'them bald and you would NOT be popular. I DO clipper my long-haired girl all over anyway for comfort and convenience (which makes piggy daddy most upset) but nobody wants to be dragging soggy wee pants behind them when the front end is trying to look pretty. But it's not the fur that's the problem really - it's just getting the xeno onto the skin so it can soak in. I put it on the bald bits behind the ears, dotted into rosettes, and finish with spots along the spine where it's easier to lift the fur.
Louise can keep herself cleaner with shorter fur - no doubt about it - and she's certainly livelier when she's not blindly running about. But I didn't clipper her when we were last treated for mites. I just did it for the heatwave, and then again more recently when she ran into a wall in a flap! And don't do the face because they need those whiskers and eyebrows for navigation. This is our Louise - delightfully fluffy but she can't see what's in front of her!
Deep breaths and good luck. It's a faff and not cheap but not a disaster and they're not in pain, just a bit itchy and annoyed. And if anypig has any as yet undetected lice infestations too the xeno will deal with the lot and then you should have a lot less shed hair bunging up your washing machine and that's win-win in my book