I can't explore the grotto, my pets just keep going unconscious even after I take them to a healer or use a revive potion on them. What do I do?

they probably aren't a high enough level

They are level 60

Well..for one thing you have only one pet and it will take some time for it to recover it's health.
However it is beyond me how you managed to get to level 60 in such a short time though...impressive :)

You might need at least one more pet for your party so one isn't taking all the damage and doing all the fighting but if you want to go it alone then I would suggest finding at least one piece of equipment that ups your pet's strength because those trolls do not exactly play nice.

Don't forget that your one and only pet is designated as a "Tank" pet which means enemies will focus on it when in battle so having at least one other pet will help things greatly.

Here is another tip I discovered from someone else. The Shadow Tree apparently works quite well for tank pets too and seems to do a better job at healing your pet as well. So....just a thought.

then you should stock up on elixirs and armor

Ok..good. You have a new pet, have you added it to your party yet? If so then go to a place like Fungus Grove first so your pet can level up quickly to a point that you can equip better armor (it helps)

Don't forget, when your pet is unconscious, it will take time for it to revive on its own as well as recover energy.

Also, judiciously use mend whenever possible, and sell most equipment. Though you pets are level 60, I believe you have not distibuted attribute points. For the earth one, put 1-2 in health and 0-2 in strength and 0-2 in dexterity. For the light pet, put 0-1 in health and 2-3 in intelligence. You can find it in the proficiencues when you click on your pet's name. This is incredibly necessary. Without this, my three level 60s would be dead constantly (which they still seem to do a lot). Open all chests. Human enemies drop gold.
Ask someone with more experience for more stuff, since I've been playing for a week.

Oops, yeah. I failed to notice that. Yeah, it is a good idea to have at least your tank pets attributes set so it doesn't get whupped so easy.
Also don't forget to equip your tank pet with something that increases its agility which, in turn, allows it to dodge attacks and take less damage.