solder trace damaged

A solder trace on a hc-05 bluetooth module has been burnt and the copper pad had fallen off how do i fix this?

Two suggestions

a) Take a fine wire and bridge the damaged track

b) Just buy a new one

But more important, why did it happen?

If you can find a part of that trace that you can solder to, you can connect to that, and solder a wire to the destination. Otherwise, bin it and buy a new one. HC-05's aren't expensive enough to really get worked up about it.

If the track was burned form the electricity flowing through it as opposed to a careless soldering iron your module is broken anyway.