Could it be wild parsnip? If so, take care, because the sap can do similar things as can the sap of giant hogweed. The leaves look very parsnippy and the roots are not dissimilar.
Mrs. Wow's ankle during our Irish end-to-end. I assumed it was giant hogweed that did this (it was May so it wasn't that big at the time) but looking up wild parsnip it may have been that.