When Marge is speed prepping the kids for school, she puts Lisa's clothes on Bart and Bart's clothes on Lisa, but after she drags them into the kitchen to speed feed them, the kids are wearing the correct clothes.
There is a mistake when Lisa is in the school's a/v room reviewing footage from the security cameras. When the camera is aimed directly at the video monitor (i.e. from Lisa's point of view), Lisa and Francine are shown wearing nose clips. When the camera is at an angle to the video monitor (i.e. you can see both the monitor and Lisa), the nose clips are gone. When the camera switches back, they are back again.
When Lisa is showing her arm burns to the bullies, they switch from four burns to three, then back to four.
When Lisa is stuffed into a locker, Milhouse is in the locker next to him and that he's standing on Ralph's shoulders, who starts to jump, which he probably wouldn't be able to do if someone was standing on his shoulders.