You have to make it through the simple maze comprised of 2 buildings, the second of which is comprised of salt and avoid the spinning blades coming from the left. Bandage Girl is in the 6th building on the right.
In order to get the bandage, you have to jump over to the 3rd building, slide on the wall and CAREFULLY jump between the 3rd and the saw blades that are closing in from left. The bandage is floating behind the saw blades, slightly above the gap one needs to jump through.
This bandage is particularly easy to get as Headcrab (PC), since it can stick the the wall of the third building and wait until the player passes through the gap of the closing saws.