Ohh boy!!
Saiyan, 40-50 kmph is enuf speed to get bruised,scratched badly and maybe evn get a few fractured bones..
I read somewhr tht human beings cannot tolerate hard impacts above speeds of 15 kmph.. So u are really lucky!
And yes, u are right, a good helmet goes a long way to save your head and your face. Btw, i have a half face helmet like u mentioned in the 3rd point. it doesnt have protection in the chin area..
I actually had a full face helmet b4, but its weight used to strain my neck like anything..so i bought a half face helmet, since it was light weight. Damn! seems like it was not such a good idea.
Take care, man! Keep ur hands of ur bike for sometime now.
