Even if packaging states the lenses are safe or sanitary, there is no governing body to ensure that is the truth, nor will the lenses be properly fitted for your pupil size.
Only contact lenses prescribed by your eye doctor, which are regulated as a medical device by the Federal Drug Administration (FDA), can be considered safe to wear. Any contact lenses that are obtained without a doctor prescription are considered illegal with potential for harm.
According to the eye docs of SDEC, it simply is not worth risking your long-term eye health for a few hours of costume fun.
Learn more at : https://www.fda.gov/medical-devices/contact-lenses/decorative-contact-lenses-halloween-and-more