Anna... btw..batteries can also explode when not attached to a charger. Just check video's on youtube. A guy lost 7 of his teeth whilst vaping...
First just want to say that I am sorry to hear of your injuries, but good to know they are not serious.
Batteries very rarely explode on their own. Something needs to trigger that event. In your case perhaps they were being over charged. In the case of the individual who lost his teeth, it could have been a damaged wrap, short circuit or even a damaged cell. But these incidents are just not segregated to vape devices only. Laptops, cell phones even flashlights, just to name a few, all have had their fair share of incidents, and even from the likes of top manufactures such as Samsung, Apple and Sony. It is a risk we take in order to be cut from the cord. What is key is understanding these risks and adopting processes in order to mitigate them. Unfortunately educating the consumer on said risks and needed processes is a difficult task.
I wish you a speedy recovery. And as much as I can understand your concerns and fears with vaping, or better put, the batteries used for vaping, I truly hope you can over come your nicotine dependency without resorting back to smoking cigarettes. Should you over come your fears with vaping, both this forum and Battery Mooch YouTube page are excellent resources on proper battery safety.
Good luck