Just started taking triamcinalone ointment for eczema and now one of my neck lymph nodes is swollen. is this a side effect? should i be worried?

Unlikely.: Triamcinolone is mid potency steroid. Over a long period of time it could potentially reduce your immune system fighting infection so theoretically it could lead to enlarged lymph nodes but it would take a really long time. So I would guess you are also having an infection, and with eczema superinfection with bacteria is not uncommon. See doctor if eczema getting worse or any non-healing lesions

Not usually.: Triamcinalone topical can thin the skin if used for long periods of time, but it doesn't usually cause a lymph node to swell. Swollen lymph nodes can occur when you have a cold, sinus problem, or allergic rhinitis. If you have fever greater than 101 that doesn't go away with acetaminophen or ibuprofen, a sore throat, cough, weakness see a doctor.