See there are some thing when we hasitate to take personal consultation but this does not solves the problem you have
pilonidal sinus ,it needs proper work up like
MRI Spine to rule out its extension into
spinal cord,if not connected to spine it needs surgery and its removal send tissue for
biopsy as you have more blood like discharge.If it had connection to spinal cord then it needs urgent surgery only by neurosurgeon.Otherwise if not operated may lead to
pyogenic meningitis which is very risky to life,if operated by other than neurosurgeon it may make a tear in dura and meningitis.So in summary do MRI Lumbosacral spine go to neurosurgeon.