A question about flash...(FZ200)

I took this photo of fire dancers who had choreographed a special number for us to commemorate a special occasion.  I quite like this picture, but I had to brush exposure over the lady's face to bring her out.

Would a second-curtain flash sync have captured her features better while leaving the fire trails intact?

Can anyone recommend a procedure for this kind of shot?

Many thanks for any insights you can offer.