Hi, I had a look on the PG website. You are started the actual treatment with the oils and the carrying agent, so you're on your way already. It makes the pigs a bit slippery to grab and I'd imagine 2 little 10 weekers are a handful at the best of times.
When you wash them, have everything you need right beside you. I wash my adult boars in the bath, and even with my DD helping we manage to get more on us than on them. When they want out they mean it 
Shavings and sawdust dry the guinea-pigs skin and feet as well as being a potential irritant (their faces are right in their)
I give mine cardboard and newspaper (no sellotape or staples) topped with hay, changed daily. Luckily mine aren't chewers.
Horse bedding suplliers will have Megazorb or equivilant that is a very fine paper based bedding or a Hemp Based bedding , but be careful with 'scented' ones, some have Citronella.- potential irritant.
There's Pet bedding like Carefresh , but the Equine bags are better value in bulk.
Though I bought a huge bag of Equine Readigrass - it's recommended for rodents, to replace grazing in winter. Not a bedding really, short and sharp.
My GP2 sneezes when he has it
.
Most websites don't recommend straw either (can be sharp and cause eye injuries, especially with babies)
Try getting them <strong>off</strong> the shavings, and combined with your PG treatment, bath, then Gorgeous Guinea, things should improve.
Good Luck <img loading="lazy" class="inline-flex mumsnet-emoji" alt="Wink" src="https://www.mumsnet.com/build/assets/wink-ClU7UaDM.png">