This maybe? But the arm tattoo appears in the 5th chapter, then again, the chapters uploaded here seem to be very short. https://www.mangago.me/read-manga/last_chase/
The guy appears from her arm here: https://www.mangago.me/read-manga/last_chase/mrk/m_chapter-11/
It is very interesting! https://www.mangago.me/read-manga/last_chase/ Chubbub helped me find it
There was a WEBTOON of a girl that would always wear long sleeves even thought it was summer then I think in the first or so chapter some water fell on her while she was walking outside and then everybody around her starts talking about all those tattoos she has