For one very specific and very hilarious reason, DC Comics’ the Flash proves to have a better healing factor than Marvel Comics' Wolverine. The Flash and Wolverine couldn’t be more different in terms of their power sets, with one relying on speed and agility while the other brute strength and rage-fighting. Their shared healing factors are basically the only similarity between Wolverine and the Flash, and after one hilarious instance found in the comics, the Flash proved that his healing factor is better.
In Teen Titans #13 by Geoff Johns and Tom Grummett, Bart Allen aka Kid Flash gets a tattoo of the Green Lantern symbol partly because he thought it looked cool and also because it protected his secret identity by throwing people off his scent. In a mere few seconds, the tattoo was completely gone though as his body healed itself and replaced the permanently marked skin in a flash. Cyborg explains to both Kid Flash and readers that it is his heightened metabolism that is the cause for his healing factor. The Flash’s body heals at an accelerated rate and it registers the tattoo as damage which it quickly heals.
Kid Flash’s tattoo was gone in a few seconds because of his healing factor, yet when Wolverine got a tattoo, it took much longer for it to disappear due to his healing ability. One of Wolverine’s mutant powers is a healing factor, an ability he breaks down In Ultimate X-Men #48. In the issue, Wolverine proves himself to be something of an expert on tattoos while hanging out with Storm following the death of their teammate, Beast. When Ororo asked how he knows so much about tattoos given that Wolverine doesn’t have any, Wolverine replies by saying, “Tats are basically scars, Ororo. They only last a few hours on me before my healing factor rubs ‘em out”.
The main thing to take away from Wolverine’s explanation as to why he has no tattoos despite having had many of them in his life is the fact that he said they are healed away in a few hours. As fans saw in the Teen Titans issue, the Flash’s tattoo disappears on-panel and clearly only takes a few seconds to be completely gone.
The Flash is the fastest man alive, every version of him linked to the Speed Force, so it makes sense that even his healing factor is faster than that of other heroes with the same power. Because the Flash’s body got rid of a tattoo in seconds and Wolverine said it takes a few hours before his body “rubs ‘em out”, it is proven that the Flash heals faster than Wolverine, no matter how hilarious that proof may be.