Is it safe to stretch your ears when you have a blowout why or why not?

No. If you stretch with a blowout it will only get worse. Blowouts can get big, nasty, and painful. If they get big enough, they'll prevent you from stretching. Not to mention that they just look disgusting and other serious stretchers will know that you don't take care of your ears like you should. Just downsize a size or two, get your ear back to normal, and take your time stretching back up.