It does look strange and yeah, I'd think she would have had hairspray which should have prevented that, so maybe it was a hairpiece. But I don't know why she would have needed it. I don't know anything about hairpieces. Extensions are basically woven into your hair to make it longer and/or fuller. That doesn't look like hair extensions, at least not any I ever saw.but it's like the top part completely flopped down, like the structure broke or something. It looks weird! I would have imagined the level of hairspray they were using in those days would keep one's hair in place in a high-speed car wreck let alone being on the giving end of a moderately vigorous slap to the face. Was it some kind of extensions or hairpiece?
(note that, despite my namesake's father's fabulously fluffy 'do, I know almost nothing about styling hair)