my main worry now is what to do about the hydras coming up in lair. No large rocks or flaming edge weps yet.
Maybe look for something else ranged to use on hydrae.
If things are going moderately well, you may have several charges of wands to start (acid works especially well), and that
may tie you over while you scrounge up something else in Lair.
Search for any shortbows lying around. Even an underskilled shortbow can tear through a hydra pretty well with several shots. A branded one can be amazing (at least for this purpose, again with a few shots) with just a few points of training.
If you see anything with summons (box of beasts - sack of spiders - scroll of summoning etc.) grab it and bring it along.
Even a sling could help if you can get enough distance.
A flail or dire flail just to finish the beastie off safely might not hurt. Potions of Lignification may also help fending off attacks for a few turns, as long as you have something to attack with that doesn't generate more heads.