Assuming it survives, it will be propagated into the population. If it confers an advantage, it will come in faster and eventually become predominant.
The other question is if this squirrel mates, is this new allele dominant over the regular color? Is it co-dominant? Is it recessive!? Seems like it is dominant as it was expressed...as the squirrel likely has one regular allele and thenthis new allele.
Of course, being darker may make it easier to be preyed upon...so perhaps bye bye squirrel and it doesn’t get passed on.
