… What do you mean by ‘no heatsink’?
Hollow pill?
We need some pics!
It could have been a junk emitter, poorly flowed onto the star causing the emitter to fry. Sk68’s are often driven pretty hard for tiny 14500/AA lights.
If the pill is just hollow I wouldn’t worry about it. Replace the emitter and star for a few bucks and you should be good.
This thread should be helpful: LEDs & Other Stuff - (Reference Guide)