Badly plugged DC adapter :(((

#1

Guys,
I know it might be totally ridiculous issue, but my first try of making my axoloti stand alone ended with red pin light and noise from output, probable cause? Wrong voltage direction in my DC adapter which i didn't check before. Now it doesn't responds while pluggin in to computer via micro USB.
My question is, did i totaly burn the core?
I know nothing about electronics that's why i didn't think about checking adapter plug before, but nevermind my lack of cautiousness. I have a friend who might help me in that issue. He has much more knowledge in that stuff and lot of exp in programming than me, but i think giving some advice what he should check in first place might get him closer to fixing the problem, of course if the core is still alive...
Any advice would be greatly appreciated!