Fighter jet game

Im a newbe currently working on a jet fighter game which involves a couple of tutorials on Kirupa. What I have made is a fighter jet where u can use the arrow keys to move up down left and right. Then I have astroids coming at it and i use the collision dectetor for that.

The question:
I have made it so when the ship gets hit it displays collison dectected like on the tutoral. Im wondering if in the dynamic text box can u make a bar like of dashes or periods and when the ship hits the astroid it subtracts some periods

Sorce Code
onClipEvent (enterFrame) {
if (_root.mover, hitTest( {
_root.text = “Collision Detected”;
} else {
_root.text = “No Collision”;
The mover is the jet and the dot is the astroid I just need the code to make it so it can add or subtract periods from the dnamic text field labled text.

Thanks in advance and im sorry if its unclear

also if the periods get to 0 can u make it to go to a frame like saying you lose