No, there is no "Benadryl challenge."
Your kids are either trying to get high or are trying to kill themselves. Stop blaming the internet and start thinking about ways you can help your teenager not feel like the only escape is to hurt themself.
shtwt is a spectrum because there's this and then some other guy will be like "oh yea i disassembled this pencil sharpener from the back of a wuhan wet market in 2004 and never stopped using it since"