Don't hit your head, or even jar it! That is the road to permanent damage. For me I became so clumsy that I just keep getting them. You'd have to put me in a marshmallow suit all day every day in order for me to avoid them. I got 7 in one year and then a year an a half later got two more. It just won't stop! It's been 2.5 years since the first one and less than a month since the last one. UGH!!!
Therefore I warn,

NO SECOND HIT!
NO JARRING!

Good Luck and God Bless!
Margarite