<prompt> Which of the following isare the side effect of using argon laser-HypopigmentationCrustingKeloid formationAll the above  <response>: Argon Laser Wavelength 488-514 nm Penetration depth of 1mm, which can be increased by cooling. Side effects: crusting and possible blistering of skin, irreversible hypopigmentation, transient hyperpigmentation, punctate atrophic or hyperophic scars, keloid formation. Ref: Lasers in otolaryngology by Karl bernd p.144 