There is always a simple and effective method to distinguish the nature of a spherical mirror, which I am discussing in this solution.
Every spherical mirror is a part of a sphere, which has reflecting surface at one of its side.
(1). If the centre of the sphere of which the mirror is a part, lies at opposite side of the reflecting surface of the mirror, then It will be convex mirror.
(2). If the centre of the sphere of which the mirror is a part, lies at the same side of the reflecting surface of the mirror, then it will be concave mirror.
As according to the question, mirrors are placed in front of our face, so may be it is not possible to determine the nature of the mirror from above method, then in that case, we have to judge that whether the reflecting surface of the mirror is raised off outside or slumped inside.
If it is raised outside, then it is convex mirror, otherwise it is concave mirror.