You get to fight a boss later on in the game that drops a charred ring- an item that basically lets you walk on lava while taking minimal damage overtime. I can't remember how far you have to be in the main story though. --- "Memento Mori" ---
You run after killing the demon guys. They don't respawn.The one on the platform thing gave me a lot of trouble since I kept rolling / jumping / running into the small ledge that I just didn't want to climb.
I highly highly advise high health, and if you get the ring from killing the centipede bosses tail, it helps a ton. It lowers lava damage to basically poison.