check the underside of the leaf where the damage is. You may have spider mites. That is just what it looks like on the top when they feed on the underside of the leaf. They are very small so you will need a maginfying glass to see the properly. If you do and you can only find a few try killing them with your fingers. If you do see some you need to also look for their eggs and crush those to. Your plant is a little young for other options but if you are lucky you can get rid of them now before they are a big problem.