This would fit into the general appearance variation of Guibemantis liber, but that species isn't known from this area, even in a study as recent as 2023. The only Guibemantis species I know about that is known to be found in this area is Guibemantis timidus, but this does not look like that species. So either there's another Guibemantis species known to be found in this area that I don't know about (quite likely), or this is an as-yet-to-be-described species.

Here is a list of all the reptiles and frogs I saw on this 2023 trip to Madagascar.

Another one, less mysteriously lumpy.

And yet another.