3cm open seam on the top — clamps and hide glue at home, or take it in?

After the season change, a 3cm seam opened on the lower left between top and rib. No misalignment, just a visible gap.

Questions:
1. Can I clamp and glue this myself with warm hide glue, or does the top have to come off?
2. If it must come off, is the whole side normally opened?
3. How long should it rest before stringing up to pitch?

It is a factory instrument for daily practice; I don't want to spend much but I also don't want to make it worse.