Is blowing things up dangerous to your face?
Definitely. Parents and other adults aren't being
over-protective when they tell you not to play with matches, fire,
fireworks, etc. Many children have seriously hurt themselves this
way.
If you're talking about the act of blowing something up, with
your mouth, such as a balloon or inflatable air mattress, ball etc.
No, not really. Just be careful not to over inflate an item. The
danger with balloons is that they CAN blow up in your face, and in
rare cases you might suck the balloon down your throat and
choke.