Lymph nodes enlarged

I had a infected pimple ( now diagnosed as a EIC) on my forehead in February.  The swelling and redness somewhat resolved when I had noticed a swollen lymph node on either side of my lower neck.  Both mobile, less than 1 cm.  Went to primary care, did chest xray(normal), lab work(normal).  Went to ENT for area on forehead who put me on antibiotics because area was still a little pink(beginning of March).  Finished these about 1 week ago.  Lymph nodes are still about the same size, decreased some.  ENT stated nodes mobile and less than 1 cm.  He did a lot of lab work all normal.  How long do lymph nodes stay enlarged after infection is gone.  Going in next week for removal of cyst wall on forehead ( hardend area still there).  Can neck lymph nodes enlarge from infection on forehead?