Hey mate... no diary=no information for us to help you out! This could be anything from a deficiency of calcium/magnesium to an infestation of bugs (have you checked the underside to see if there are any bugs/eggs?) ... Is this a young plant? Are these the bottom leaves or ones near the top? You really need to start a diary so when problems/questions pop up, the community has as much information as possible and can give better advice. Sorry....