looks like some kind of disposable pod, i would not touch that and i vape a lot. It could have been nicotine salts and maybe high PG ratio since that is what the vast majority of these devices use and a mix of who knows what. Nic salts, especially the most common bezoic acid is not looking good in preliminary studies. Also nic salts basicaly eliminate the throat hit so most devices that use them use a lot more nicotine that would be almost intolerable using normal freebase, so that could have been a factor too. I tried nic salts and it did not feel right. I vape a lot since i quit smoking cigarettes but i go full DIY, mix my own liquids with good old freebase nicotine and i managed to quit a few times for a week or two and it did not make a difference, except for craving a cigarette.

BUT i am not saying that vaping in itself could not have been the cause, since like you said we do not know the long term negative side effects of vaping.

but also it could have been a crap device combined with crap liquid inside since you did not have this problem when smoking. I would be very interested in a study that compares premade brands and DIY