The following are the opinions of some of the Maraj’i in regard to undergoing surgery to remove brown spots from the skin through laser technology:
Grand Ayatollah Khamene’i (May Allah prolong his life):
It is permissible if it does not involve haram looking or touching and does not cause notable damage or harm to the person.
Grand Ayatollah Sistani (May Allah prolong his life):
If you are in Haraj (a very difficult situation) it is permissible to do so.
Grand Ayatollah Makarem (May Allah prolong his life):
If it does not involve any other haram acts or doesn’t entail notable harm to the body, there is nothing wrong with it per se, but if it involves any haram acts (i.e., haram looking or touching), it is only permissible if there is Zarurah (a very urging need).