Diagnosed with me 18 months ago. clear blood tests. ultrasound of neck shows several lymph nodes but all under 1cm. is this ok or could it be lymphoma?

< 1 cm SA = good: Lymph nodes with short axis measurements of less than 1 cm are not, technically, considered adenopathy, although widespread early metastatic disease cannot be excluded (would require a pet scan). The lack of anything else worrisome per history is reassuring. I don't know what "me" is, but ultrasound surveillance of the neck nodes in 4-6 months to ensure stability would be helpful.