Why do my hands swell up when I mow the lawn?

I used to have the problem similar to this. I am guessing that you have a gasoline mower. The swelling can be coming from the vibration of the mower handle. Do you feel your heart beating in your hands when you stop? Try padding the handle with some pipe insulation. If not mabye you are alergic to grass????

You could be allergic so wear gloves, or something like diabetes and blood pressure issues?

me too-if i am dehydrated. Try drinking lots/enough water when you're out doing yard work.