Blisters on incision line?

Kathy, CALL the doctor. I had this happen. Mine was called a seroma, and it was basically filled with serous fluid, an oily liquid almost like cooking oil. It is a normal fliud present in your abdomen but in my case the incision line opened up and the fluid was drawn to the tiny hole which then siphoned it up tothe surface where it formed a blister, opened, and was a small hole at the bottom of my incision i had to pack it with antibiotic ointment and bandage it for about 6 weeks as it closed up again. It wasn't a serious complication but they put me on levaquin antibiotics for a few weeks because anytime you have a wound reopen you are at risk for infections.
Here is a picture of me at 6 weeks post-op when the blister first appeared.
http://home.xnet.com/~countzi/mini-me/sitting6wks.jpg
I don't share these pictures much but I am gad now I took so many and ones showing all the progress over the last 18 months, including the good and the bad, like this wound seroma... Hope the info helps.
Wound healing issues are nothing to mess around with so call your doc NOW just in case.
Colleen