Nodemcu Amica V2 and 12v in 3.3pin (ouch!)

Dear all, I really hope this is the correct forum.

I usually use a Nodemcu Amica V2 based on ESP8266. As far as I understand, it is something similar to arduino. At least, I can use Arduino IDE to program it.

Yesterday I made a stupid error. I feeded 12v into the 3.3v pin. Actually I tried several times. (Please please please double check your breadboard, especially when you are tired!). Well, the point is that now I am not able to get it up and running if I use the 3.3pin (with a proper 3.3v source) nor the Vin pin (e.g., with a 5v power source). BUT it works perfect if I connect the microusb cable to my pc (i.e., it turns on, the firmware works, I can see the usb serial converter attached as a device).

Do you have any idea whether I can sort of "fix" this board, or should I just use it for development purposes attached to my pc?

Thanks! MJ

Please check power section. I have attached schmatic for reference. https://raw.githubusercontent.com/nodemcu/nodemcu-devkit/master/Documents/NODEMCU_DEVKIT_SCH.png

weather particular IC takes input and gives .3V3 output. also check weather IC gets heatup when u given supply. Other information is given in schmatic itself