Barney's Farm - Amnesia Lemon bad seedling?

think you give it a bit too much light too soon... leaves look tight -- the growth nodes look very close together from this angle, which can be deceiving. early leaves often have blemishes. yours look fine. mybe a little coloration on newest two leaves? if not temperature related, it's just genetics. but if the growth nodes are very tightly spaced, it's probably the intensity of light. it may take a few days and you may need to ramp back up the power once it does start growing, but until then give a bit less light. watch resulting distance of growth nodes and adjust based on that.. avoid extreme stretch, avoid extremely tight node spacing. it is your guide to light intensity.

No diary = no information. Find a VPD chart and check the relative temps and humidity you're growing in... slow growth is often a result of a bad ratio between the two. Good luck...