Cracked screen and won’t power on

My Apple Watch was damaged when I was involved in a car accident, before the accident I saw the time and functioned as usual ,had no damage prior whatsoever, after the accident the screen is cracked with even the glass coming off a little bit as well as it won’t turn on no matter what. Even if I’ve had it on the charger for up to 24 hours; so how would I fix the screen as well as see if the battery is damaged or just needs to be replaced entirely?