English translation

I like cycodamo's translation for that problematic phrase. I think the idea is that his youthful good looks have been eaten away. My only question is whether "venas" refers to literal veins or the slightly less common use of "vena" as a character trait. But, I'd go with the more literal version since use of "vena" as a character trait is almost always used with an adjective.

However, I do have a couple of other suggestions. I would actually be tempted to translate the refrain less literally to get more heartfelt meaning. Something like "Not again, please, I am tired and my heart can't take it."

This phrase is mistranslated. "Malo, malo, malo eres, no se daña a quien se quiere, no!" It should read, "Bad, bad, bad you are, you don't hurt those whom you love, no!"

I am also tempted to translate "malo" as evil. There is nothing wrong with "bad" it just can suggest nothing more than misbehaving whereas evil leaves no room for a more playful interpretation--especially as she calls him a devil later in the song--if that is really what is meant rather than "débil" meaning "weak". Both would fit the context, so not sure if "dévil" is really what is said or if it is an error in the transcription.

I am not completely confident about what is meant by "la penita de mi corazón yo me la tengo que tragar con el fogón" but I think it is more likely to refer to having to swallow the pain in her heart with fire rather than by the fireplace as it is translated here.

I really like the translation of "Y ahora yo me fumo un cigarrito y te hecho el humo en el corazoncito" as blowing smoke into your little heart. Nice!