Do the leaves look like this photo? If so I think you have the citrus leaf miner. I got the same thing - I've talked with a number of people and they say it's hard to get rid of without using a systemic pesticide, because the "Miners" are in the middle of the leaf and aren't really affected by sprays that on the outside of the leaf.
Here's the University of California official page www.ipm.ucdavis.edu/PMG/r107303211.html
and here's one from Florida www.themulch.com/articles/gardening-link...of-florida-extension
I really try to do everything as pesticide free as possible, but I ended up using a systemic product from ortho that I bought at Walter Andersen Nursery and it really worked. The older trees didn't seem to be hit as hard with the bug, but the young plants with lots of new growth really got hit hard with the bug (that's why I ended up using the ortho).
I hope this helps!