It's hard to keep track how many different versions of Harrison Wells that Tom Cavanagh has played since The Flash debuted in 2014. The former Ed star came on in the first episode as Wells in a wheelchair, dealing with the fallout from the particle accelerator explosion… except this wasn't really Wells, but Eobard Thawne pretending to be Wells. Then in flashbacks we got to see Cavanagh play the original Earth-1 Wells that Thawne killed.
In Season 2, we got to meet Earth-2 Wells, who came over to try and stop Zoom and save his daughter Jesse. He went back at the beginning of Season 3 after helping the team find another Wells, this one going by H.R. who was around for the season before sacrificing himself to save Iris West. And in the episode we got to see a few other Wells, including a mime version.
The new season, Cavanagh will again be playing Earth-2 Wells, but he won't be the only Wells we see this season. And what we do see of the Earth-2 version will be quite an emotional struggle. Executive producer Andrew Kreisberg told EW.com:
"He's a genius, and his daughter is safe, and she's The Flash on Earth-3, and he's one of those people who's realizing that he doesn't have a life. So season 4 for Harry is really realizing what he's missing in his life and what it is he needs to become a better, more complete person, and so he's going to be going on a fairly epic emotional journey this season that is tied to The Thinker's plan."
I think we're going to need a website dedicated to keeping track of all this: All's Wells That Ends Wells.