Typically, this question would arise years after your Lasik procedure. If it has only been a short time since having Lasik and there is a noticeable deterioration in your vision, you should see you eye doctor. While it will be completely safe to wear contacts, a rapid deterioration of your visions should always be checked to ensure there is not another cause like Keratoconus.
For some patients, Lasik may not have been able to fully correct your vision. In those cases, it may be advisable to wait up to 3 months for full healing and using glasses during that interim time period. Also depending upon your prescription strength prior to Lasik surgery, there could have been enough cornea removal during your surgery that will make fitting you with contacts a little more problematic.