fixing lighting issue

On the grass nails, I set lights directly around and why does these nails looke like that??

Not really enough info to answer the question, I think. What kind of material set up are you using? What look are you trying to achieve? Provide more details of your scene, materials/nodes, and what you want. Try and make the question a little clearer, because I’m not quite sure what the problem is just off of what you’ve provided.