What do I do when a costume piece breaks backstage

What to do

1. Don't panic: every competition venue has other parents with repair kits, and most costume emergencies are fixable in under 10 minutes with the right supplies. Do a fast triage: is the break cosmetic (one loose rhinestone) or structural (a broken strap the dancer can't go on in)? Cosmetic repairs can happen in parallel with warmup. Structural repairs need to happen now, with everything else on hold.
2. Loose rhinestone, stone row, or small trim strip: fabric glue designed for rhinestones (Beacon 527 Multi-Use Glue or Gem-Tac) pressed onto the back of the piece and held firmly against the costume for 60 seconds holds through performance. Have the dancer stand still for 2-3 minutes after. The glue sets faster under body heat. Do not use super glue (Cyanoacrylate) on fabric: it wicks into the surrounding material, creates a stiff patch, and can ruin the costume. The competition first-aid and foot-care guide covers what to pack in the emergency kit.
3. Peeling applique or bead trim strip: use the same fabric glue along the full length of the lifted edge, press, and hold with a binder clip or your fingers for 2-3 minutes. If the strip is long or the dancer is about to go on: safety pins on the inside of the costume along the peeled edge, as close together as practical, hold the trim flat until glue can be applied properly after the number.
4. Broken snap, hook, or clasp: a safety pin at the same attachment point holds for a full competition day. Pin through both sides of the closure, parallel to the opening, so the pin itself bears the stress rather than the surrounding fabric. Use a pin size appropriate to the material: a large safety pin through chiffon will tear it. Two medium pins are safer than one large one. Reinforce with a second pin if the closure bears weight or stress during lifts.
5. Dropped or unraveling hem: no-sew hem tape (Dritz HeatnBond, Steam-A-Seam) activated with a flat iron or even a straightening iron on low heat re-bonds a fallen hem in 60 seconds. If no iron is available, fold the hem up, press hard with your fingers for 30 seconds, and pin the inside with safety pins every 2-3 inches. The hem will hold for a performance. Re-iron after the event for a permanent hold. For a raw edge that's unraveling, clear nail polish along the edge stops the run immediately.
6. A strap, spaghetti strap, or shoulder seam that pulled away from the bodice: this is structural. Safety pins as a stop-gap, but the dancer needs to know not to put full weight on the repaired side. A small hand-sewing needle and matching thread is a permanent fix in 5-7 minutes: a quick running stitch through the seam allowance is enough to hold through a routine. Most moms who've been at this for more than a season carry a travel sewing kit in the dance bag. If the repair isn't solid enough, pull the number and get it properly sewn before the next event.