I never got around to testing the charm necklaces? Is that what you used got the healing charm? Did you try the basic and the advanced necklace?
The more expensive/advanced necklace lets you have a temp skill from another class -- that's what I used for the healing skill. Of course, I think you're limited to whatever charms other players have crafted and sold to the vendor, or to charms made by friends/guildmates or others willing to craft them for you.
I didn't try the basic necklace because there were no mesmer/elem skills I really wanted to try that I didn't have already. It's a very useful tool though for testing out class/profession skills without having to spend money or skill points to train them or to capture it with a signet of capture.
This game really does a great job of giving so many options for getting and testing skills:
- train in a skill (costs increasing amount of gold and costs skill points, which are limited in number)
- capture a skill in a signet of capture (costs fixed amount of gold, but you have to time your capture to when a boss you've targetted is using it -- if you're sly enough, sometimes you can target a boss without engaging in combat and catch it casting something on themselves as it wanders around).
- temp learn a skill from any profession or your own profession -- small cost and no permanent loss of skill points
- permanently learn a skill of your own profession from a skill charm by using a skill ring for your profession -- free cost and no skill point drain but limited availability since these rings only drop from bosses