I noticed this morning that my mare has a lump under her belly just forward of her udder. Early this morning it was the size of a 20 cent piece, by lunch time it was about 3 inches accross and it hasn't gotten any bigger. When you look at her side on it hangs down about half an inch. She also had a couple of other lumps that looked like mozzie bites on her shoulder and flank but they went down very quickly. It is not sore to touch. Could this be another insect bite or something more serious? Any advice appreciated!