We have treated ours with Beaphor stuff, which I'm fairly sure is similar, active ingredient is Ivermectin. Ours were licking each other after I applied it last time, and I put on a thread asking the same question. Ours were fine, I know it's not an ideal scenario, but you can give Ivermectin orally anyway. It's just the other ingredients which aren't really designed to be ingested! They are nosey aren't they? I cuddled Amber for ages yesterday, after I put her back the others were smelling her fur where I'd stroked her! Their sense of smell must be pretty good!