As Stilton said let the Ng stabilize for 2-4 seconds before introducing fuel on startup.
The white smoke from the exhaust is most like residule fuel left over from the aborted start. Keep cranking after the aborted start to clear it up to the max starter time limit. You can also have a dry start in before your next proper start attempt to make sure you have cleared all fuel and some of the hot air.
Try parking the aircraft into wind on shutdown and startup. This will help keep the ITT down on startup.
Without knowing the pressurization system on the Meridian I can't comment if that was the cause of the hot start. Chat to your maintenance engineer and get as much info out of them as possible on operation and techniques. Although I don't think the engine is fried I would be interested to know if there is any damage.