Hi there, have u come across a manga in the 90s where a alien stay inside a boy's hand. The boy uses cloth to cover his hand because there is a triangle logo on his hand. He will transform into superhero using the alien's power when he is in danger.

parasite

Oh, it's different. Parasite the alien can take control of the body of the human but the one I can recall, it only gives superpowers to the human and the human can transform 😎

this ?
https://www.mangaupdates.com/series.html?id=48822