Hey there. It does appear these holes are sinuses
. It is very possible for some reason (including possibluy ingrown hair), you have developed an infection or lymph
nodes in the area have got matted & evolving into a condition known as hidradenitis
. Antibiotics & anti-inflammatory agents are the order of the day & a visit to your local dermatologist
or surgeon is suggested asap to prevent this from growing any further & nip it in the bud so to speak before it becomes chronic. Cheers & Good Luck!