Help - killed my nexus 4

[pigsinmud]

I plugged my phone in to the car charger this morning. Realised it wasn't charging so flipped the 'on' switch on the car charger and my phone died. Can't turn on and won't charge. It is an LG Nexus 4. It was fine until the car charger and can only assume there was a power surge. What can I do?

Can anyone help? I've done the usual hold power button & volume for ages and nothing. I've had to nab dd2's phone (dh's old phone from years ago) and it's horrible. Dh's idea is he'll get a new iphone and I can have his old one. Humph!