Apparently, this is a common problem in some people with neurological problems.
Spastic neurological problems, to be precise.
And a local rehab setup has been testing a herbal salve, containing St. John's wort, meadowsweet and calendula, made with an oil and beeswax base.
It works much faster than the other things which they could consider throwing at the problem, and it has another plus: it doesn't disrupt the digestion, like antibiotics would.
I expect that balsam poplar buds would work as well - they didn't want to try a salve with only St. John's wort and calendula, as the pain from the inflamed cuticle(s) apparently is a factor in one or the other other symptom these people get. Thus the need for the inclusion of a painkilling herb.
And they swab with critter-killing things before applying the salve, to avoid the problem with anaerobic bacteria trapped beneath a layer of salve.