HELP ME PLEASE

HELP ME GUYS Hi guys, I put my charger on an extension cord that I've had for years and it's never had a problem. Today while my cell phone was charging, it exploded, it didn't catch fire, the charger is intact, only one burst with the charger in the extension and the extension started to smell burnt but not the charger and the wire, what should I of? change the extension? or the charger too

ps: the extension still works too, but it still smells burnt, what should i do?