Just downloaded Fallout 2 and started to play. I have a question: is it possible to rest somehow during the Temple of Trials bit? I don't have the Pip Boy yet, so I have no idea how to rest, and unless there are some healing kits lying around I have no idea how I am going to survive those insects. I've built a real sharpshooter type character who tends to miss a lot with the spear.

You can't rest without PipBoy.
Just run through the temple, it's possible. Or reload a lot.

There are some healing powders, along with an antidote potion or two, in the chests in the temple.
Does your char also miss when throwing the spear, or is his/her throwing skill better than his/her melee skill?

Depending on how many AP you have you might be able to use the trick I use for the temple when playing a sharp shooter.
Punch/spear the ant and then run away, the ants close in on you but don't have enough AP to attack, keep going until they are dead

You can use the "first aid" and "doctor" skill to heal yourself. Even with very low skill you can be successful, just retry until you succeed.

When you're injured always use those healing skills as much as possible before resting, even if you have only 15 percent skill (=success chance) the average healing speed will be faster than resting and you even gain XP for using your skills.

As others suggested, use the healing powders (although they lower your stats), or try using first aid or doctor on yourself. I play sharpshooters most of the time and I am usually pretty bad with melee weapons at the start, but it's easy to trick the ants/scorpions, just try it a few times. Hit them once, then run away, or try two hth puches, then run away, you'll get it right after a few tries. If you do it right, they only have enough action points to get into your melee range, ending their turn in front of you, not being able to attack.

I can't remember now, but I think for ants it's two puches, for scorpions it's one spear attack or something like that. Just make sure you don't get trapped in a corner, run around in a large circle if possible. If it's not possible and you hit a wall, miss one of your attacks, that makes up for having to run past your enemy.

It's definitely not the most enjoyable part of the game.

Ah, yes, the Doctor skill. If you use it 2-3 times, and kill enough enemies, you can actually get to level 2 before exiting the temple.

I'm doing a playthrough as Chitsa, who isn't exactly a melee powerhouse. Using a combination of all the strategems described above I've managed to get to the final section with about 10 hp left and level 2 (from using First Aid and Doctor until I cannot use them any more, from 'exhaustion').

If you game it, you get get a lot out of the Temple of Trials it seems (XP anyway).

I found this thread from a search on "resting Temple of Trials," cause if I CAN rest in there, and then use my healing skills more == more XP. But if not, no biggie. I'll just use the healing powder and carry on.

You can get clvl 2 and a bit more if you explore the Temple of Trials fully.

To make your life easier get used to such tactics as:
- hit&run against melee monsters. The ant and scorpions will not attack in the round if they moved 3 hexes.
- save regularly.
- no matter how low your skills are, you can do all key things here, and probably deactivate all traps in the appropriate section.
- there are some healing equipment.
- unless you are a specialist for melee weapons, stick with unarmed for here. Costs less AP, and the aim% might differ too. Later guns give high bonus to aim, so you will probably abandone unarmed and melee unless specialised.
- there are some healing equipments.
- the final fight can be avoided by speech tagged or steal (no need to tag it). Or just save&reload every turn - the guy has a good % to miss too.