Bypassing Telegram geo restrictions?

Will changing my account's telephone number from a U.S. number to a Mexican number get rid of the geo restrictions when using a VPN or do I need to make a fresh account with a Mexican number?

What are your geographic restrictions? What are they?

I don't think there are any?

Most web services are already keeping track of VPN IPs, so it might not be an issue with the account's phone number. You'll want to consider using a proxy instead of VPN when masking your IP. Particularly for mobile proxies, you're connection will appear as any other mobile devices from the proxy's location and none would be the wiser.