My guess is leaf miner damage. Hard to spray etc... because the leaf miner bugs live inside leaf. I just tear the damaged part off. They liketo get my chard plants.

Should i get some sort of spray for it?

Leafminer trails are typically more serpentine -- winding -- than that.

Difficult to see detail. Can you post a larger image?

heres a bigger picture
http://i956.photobucket.com/albums/ae46/the57/tomato-leaf.jpg

Here is a link that might be useful:

If it were leave miner bugs, I'd tear the leaf off and throw it in the garbage. But, it does not look like leaf miner damage on your larger picture.

Is there anything on the underneath side of the leaf?

Looks like some very small critter took tiny nibbles from the leaf surface. If that's all the damage there is, not to worry.

Seems to be getting worse, on more leaves now, theres nothing on the underside of the leaf, heres a new pic

Here is a link that might be useful: