What is the ruling on adopting a fatwa that permits something while other scholars do not permit it, and does one incur sin if one acts upon the fatwa of permission and it later becomes clear that the correct view is non-permission?

A Muslim should adopt the opinion supported by the strongest evidence and the most cautious approach, in order to avoid disagreement, clear his conscience and reputation, and steer clear of ambiguities. There is no harm in removing hair from between the eyebrows.