Answered by Shaykh Amjad Rasheed
I have had myself tattooed in the past. Later on, I realized that I had made a grave mistake. Is it obligatory for me to repent, or must I remove the tattoo?
It is obligatory for you to immediately repent. According to our school, it is [h: also] obligatory to remove the tattoo, since it constitutes filth with which one’s prayer is not valid, unless one fears [h: that removing the tattoo will cause] harm, such as the occurrence of an illness, delayed recovery [h: from an existing illness], or the occurrence of an excessive mark on the face or hands, in which case it is not obligatory to remove it.
Exceptions are, however, made for someone who was tattooed during childhood or while insane. The great scholar al-Shabramallisi also made an exception for someone who was tattooed before becoming Muslim (cf. Hashiyat al-Shabramallisi ‘ala Nihayat al-Muhtaj). For such a person, it is not obligatory to remove the tattoo after accepting Islam. His prayer is valid with [h: the tattoo], and something that contacts [h: his tattoo] does not become filthy, since he did not believe that it was unlawful.