I got a cold sore (which I get often) about 3 days ago, and developed this marble-sized swollen lymph node under my chin a day after the cold sore appeared (which hasn’t happened before). It was tender to touch at first but now it’s painless. Does anyone know if this is normal? I’ve read about painless swollen lymph nodes indicating serious illnesses so I’m a bit worried. Thanks for any help you can offer.