Battery clip screw head broke off?

Replaced the battery on my late model Iphone4 - all went well until I put the battery clip screw back in (my phone only had one screw) wyfi antenna was in place - screw went it but the Head snapped off??? broke way to easy????

So, screw shaft in place but NO head?? put phone back together, wyfi working and phone powered on just fine...

since the clip snapped in place, will that missing head cause a problem?? or should I 'try' to back the screw shaft back out and get a new screw - not sure how easy that will be??

Michael