Welcome to Healthcare Magic
Typically three doses with one or two booster doses is recommended. You cannot tell by just looking if the fluid has been used but that is not a matter of concern. If the blue square has turned dark as the colour of the dark surrounding circle then it could be ineffective. This is a sticker seen on the vaccine
vial in some countries like India. You can get your HBsAg serum levels estimated to know your protection level if more than 10IU/L it is safe.