I've been having night sweats, itchyness and exhaustion for awhile now. About 7 weeks ago I found two raised lymph nodes on my neck. Today I had an ultrasound on them and was supposed to have a biopsy.

i felt like it was really rushed and was told that they think they're benign and therefore refused to do a biopsy.

How accurate is an ultrasound to see whether they could be cancerous or not? I thought only a biopsy could determine this?