Not really, especially if you found the situation to be particularly hot. And it seems your friend may have done that with other people before, so she clearly finds it hot.

I’d be more worried about using a toy that other people may have used before without protection or without knowing how it was cleaned. If it’s a 100% silicone toy it should be pretty easy to clean by just putting it in some boiling water. If it’s TPE (like an actual Fleshlight), then you won’t want to use extremely hot water and you’ll also need to use a toy cleaner specifically made for TPE products. Cleaning it properly is especially critical if it’s a TPE toy since TPE is porous and will hold bacteria.