Your PI probably is NOT dead, no amount of processing power for however long will "fry" a PI, if it gets too hot it will simply work slower to stay cool, it will not damage itself.
what is far more probable is that you managed to scramble the contents of your SD-card. you MUST cleanly shut down your PI AND wait several seconds after that before removing power, to avoid that.
not measuring 3.3V on the 3V3 output is worrying, but possibly a result of measuring error, but note that shorting the 3V3 output will probably cause destruction of the PI. but lets not assume that this has happened.
try what happens to the temperature of the main chip if you turn it on, without and sd-card inserted, it should stay cold (as it does nothing), if it, or any part of the supply (parts near the micro-USB input) become hot, then you might have blown the PI up, note that the LAN chip works independently so may become warm, but not hot.
when measuring the voltages on the GPIO's, be very careful ! one slip with a probe, that shorts two pins together, may potentially damage the PI.
Always connect the black (negative) probe not to a GPIO pin, but to any metal of either the USB, ethernet or HDMI ports, as these are all connected to GND, and are a reliable and safe point to connect to GND.
To try to get back to a working system, I would recommend re-imaging the sd-card and writing a new copy of Raspbian to it using Etcher.
you may also read my boot problem sticky in the beginners (our double checking ) section, it gives you all the know information about boot problems.