i have acne like spots on shoulders, arms and legs
with hard white cores in them that are slow to heal and scar - often leaving dark marks - as you describe - also hardly at all on my face
has the characteristic hard white/pale grains of material in the spots
i do not think it is really acne as such - though it looks similar
acne does not have hard cores - this is something else
a few members here report a similar thing - we have discussed this here in the thread called "gritty Bumps"
https://www.healingwell.com/community/default.aspx?f=30&m=4241748i am not sure exactly of the cause - but i do note that it often seems to be reported by those who are moving forward with their treatment and feeling better in other ways - eg less fatigue - so in a way it could be a good sign of sorts
so i wonder if it is in fact a sign that the immune system is staring to become more active at finding and attacking the pathogens ( both bart and lyme live in the skin ) - but that this also causes more bacterial / cellular debris that has to go somewhere - and collecting in pores is an obvious place for it
( the spots i have seem to be mostly in pores often around a hair follicle )
the puss in normal spots/acne is mostly white blood cells that have massed around and are digesting the bacteria found there - so i wonder if these hard white cores in our case are a similar phenomenon ? purely speculation / guessing on my part.
i am not sure what the best treatment options are - especially if its being driven from within - it may be that topical preparations are only partially effective.
another member here - Rainy Cloud - is suffering similar issues and is experimenting with topical ivermectin on the effected areas - with, i think some, promising signs
maybe join the discussion on that thread and keep us posted with anything that you find