The trick, of course, is knowing which Wells family is yours. "Scotland" doesn't really help a tremendous amount, although it does allow us to eliminate, say, an armiger named Wells in Kent.
But Burke's "General Armory" lists some 18 different coats of arms for various Wells, and 24 for Welles, not always with a geographical designation. And, of course, there is always the distinct possibility that _none_ of the arms listed in Burke's for various Wells/Welles individuals belongs to anyone in _your_ Wells family line.
With more specific information about your particular Wells family in Scotland, we might be able to check some of the Scottish armorials (or you might be able to find something yourself by searching the index of the Lyon Register found on the website of Scotland's People at scotlandspeople.gov.uk), but it's very difficult to track down a coat of arms with just a bare surname and country.