I knew going in that Age of Worms would be taxing on the cleric/healer(s) of the party, if any. The acid beetle swarms can devastate an entire party in moments, and once you get to the temples in 3FoE, there is little to no "friendly" ground where you can rest. I didn't want to overload the group with magic items, so I stole a page from d20 Modern and added the following tweaked ruling to the uses of the Heal skill. Hopefully, this will be as helpful to someone else as it was to our low-level party!
Restore Hit Points: With a DC 15 Heal check, if a character has lost hit points, the character can restore some of them. A successful check, as a full-round action, restores 1d4 hit points. This number increases by +1 for every 5 ranks you have in the Heal skill (i.e. a character with 10 ranks in Heal can restore 1d4+2 hit points on a successful check). The number restored can never exceed the character's full normal total of hit points. This application of the skill can be used successfully on a character only once per encounter, or once per day if no new injuries arise.
That sounds a lot like Skill Tricks. Have you taken a look at the Complete Scoundrel? I think you would like the concept if you haven't seen them already.
Have you considered just dropping in a clw wand a little early? That should free up some resources.
Or they can buy one after they find any significant amount of treasure at all. Truth is that heal skill is going to be completely overshadowed in a level or two by the cure light wounds wand. Players that take it are actually making a mistake as those skill points will be more useful somewhere else and by level two Cure Light Wounds wands are easily available. By 3rd or 4th there a dime a dozen. Skill points on the other hand don't grow on trees.
That's a good way to reward characters that have the heal skill, I think. I've rarely seen PCs use it beyond the occasional stabilization, but long term care for poison or disease? They would rather use magical means.
And the second adventure has plenty of opportunities for CLW wands, so if you have a divine spell caster and a paladin/ranger/whatever, it shouldn't be as dire as in the first adventure.
Have you considered just dropping in a clw wand a little early? That should free up some resources.
The current party cleric has a +10 Heal skill check, including his Wisdom modifier (which he bumps every way he can, as a cleric). He has very few ranks devoted to the skill, but he makes the DC 15 check the majority of the time. When the party is beat down and completely devoid of spells due to hitting more encounters than expected, his couple of ranks show the points are far from wasted.
The party does have cure wands, they are all over the AoW adventures. During and recovering from the fight with Telakin, the party used an entire 20+ wand of cure moderate wounds. Then, the Heal checks came out.
You may be surprised what the players see as a waste of skill points.
We have started using 1d3 + lvl for Cure Minor Wounds I think that came from DD Online.
One of my players invested heavily in Heal for RP reasons so I gave him a skill check to heal Heal check - 25 hit points. Never ironed out much details for it 'cause he stepped in the wrong elevator in WC and ended up in dire need of resurrection nevermind healing.
If you want to stay close to the rules, hand out a CLW wand with partial charges. CLW in a wand costs about 15 gp per charge. You can either place this treasure, or make it available through one of the clerics in or near town (Valkus Dunn, Jieran Wierus, Nogwier, or the cleric of Wee Jas). I pretty much hinted, leaned, and pushed my party to lay down the bucks for a CLW wand early, and now that they're about 10th level, everyone who can use one keeps one in the inventory (party has a bard, paladin, and cleric/ranger--two secondary healers has kept the party from TPK more than once.
You may be surprised what the players see as a waste of skill points.
Well it certianly won't unbalance anything. I'll say that much for it.