Well im stuck with all my characters on low hp in the Hive and ive gotta kill some guy for a quest but i cant rest ANYWHERE and i have nothing to heal myself with, so what am i supposed to do? is there an inn somewhere?

Out of top of my head, if you can make it to Ragpicker's Square you can rest at Mebbeth's. Just south of Mortuary entrance is a Tomb where you can rest as well.

Also, take note that sometimes you have to talk to someone (like house owner, etc) to initiate resting.

There's also a house down south, east of the Gathering Dust bar. If you can complete this man's quest for him (which doesn't require combat and is relatively short) then he will allow you to use his home for resting, if memory serves.

You can also rest where you appear when you leave the mortuary through the portal. Getting killed is also a way to get healed to full HP again.

You can rest in the Flophouse, if you don't mind paying (five coppers). But it's so close to Mebbeth's house, where you can rest and trade items.

Just die.

Yeah, but dying doesn't heal the rest of the party, does it?

Mebbeth is your best bet. She is capable of instantly healing the entire party at no cost. This way you avoid the minor inconvenience of having to rest multiple times to either 1. fully heal, or 2. return to daylight if you finish resting during the night (as daylight is easier on the eyes).

Mebbeth also offers free resting, if necessary.

She can be found in a hut in Ragpicker's Square, two areas west of the area containing the mortuary entrance, monolith, gathering dust bar, etc..