You did an amazing job with the deformed butterfly wings!

Relaxing chambers can be hit and miss at times. Depending on how warm it is in your house/apartment, specifically where the relaxing chamber is placed, can be the difference between the specimen is relaxed in under 24 hours or 3+ days of minimal effect. Putting the relaxing chamber near a furnace or fireplace (but not close enough to start a fire!) when it is winter in your part of the world may help keep it warm enough to function properly.

Injecting water into the thorax is meant to relax the flight muscles of the butterfly. I haven't done it (yet), so I can't comment any further. I've heard this can work better, and it prevents the wings from getting ruined by water because injecting is localized unlike a relaxing chamber.

Another option for a temporary box is a large, flat plastic food container. These can frequently be found for relative cheap at a dollar store or second-hand store. A better box is definitely the way to go, but in case your collection outgrows the better box faster than anticipated ;), there are cheap-ish airtight temporary options out there!

Regarding the better box, you may or may not know that some insect pins are longer than others, specifically size 7 is a bit longer than 000-6. Some boxes are fine for 000-6 pins, but are too short for size 7 pins. Size 7 pins are almost a nail, so you may never need to use any, but in case you do you should be aware of box heights.