Blisters after cutting grass?

Every time I cut a lot of grass, maybe when the grass has gotten taller than I would normally let it, I break out in blisters wherever the grass "splatter" has contacted my skin. But not immediately, it always takes about 2 days for them to form, they start off as just red marks, not raised or itchy or painful, just red marks, then they turn to blisters. Not huge blisters, but blisters none the less. They are filled with a clear liquid and are very easy to burst, they're not painful or particularly itchy and they go away after a few days. This definitely has something to do with the wet grass that splatters onto my skin from the strimmer as this is the only time this happens. If I burst one of these blisters, I can almost watch it refill! Takes maybe less than an hour to reform and be just how it was before I burst it! Bursting them does not appear to cause them to spread. Anyone else experience anything similar? Any ideas what it is?