All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
We do not think that it is permissible to resort to tattooing again in order to cover the first tattoos even if it is a cross or a tattoo of a living creature. Even though tattoos are forbidden and it is an obligation to remove them –as discussed in Fatwa 82394 –however, removing them with another tattoo is not permissible as this is using what is forbidden again. It should be noted that when one is unable to remove the tattoo with what is permissible, he is not sinful provided he had sincerely repented from having done it. Allaah Says (what means): {Allaah does not burden a soul beyond its scope.}[Quran 2:286]
As regards wearing long-sleeve garments to cover your tattoos, it appears that you are not obliged to do so. However, if you do so in order to cover the crosses or tattoos of living creatures which you have on your arms, then we hope that Allaah will reward you for doing so.
Allaah Knows best.