Yeah, they diverge in a few ways. Especially retconning plenty of their own actions here. Such as two Rhinos.

You know, the first thing you think of when you think of electricity is dental work, so the gap in his teeth is fixed.

https://twitter.com/genepark/status/1035950625232699392?lang=en

It's probably because when he traveled to Earth-616 his look changed since the things he had on him in The Amazing Spider-Man 2 were gone

Plus he wasn't blue anymore so that was probably the cause of his change of his hair and teeth

There's also a webbverse Carnage in Amazing Spider-Man 2 game

Due to a difference in electricity he changed I presume. He keeps on mentioning how there was a new form of energy (he wasn't just talking about the arc reactor the other parts of the world with electricity shocked him too)

As @Superbattleshipyamato already linked to, Electro changes during his initial transformation in TASM2. The teeth were fixed in that part, and assumedly it improved his entire body (we haven't mentioned the abs he also received, for example.)

My guess is that when he loses his connection to electricity in NWH, his body drops the blue tint because he's been so suddenly cut off after being directly linked to the power grid at the end of TASM2. The sudden loss of power robs his body of the necessary power and his human form re-emerges. But the form itself is what he'd be like during TASM2 if he wasn't covered in that weird blue skin. It could be that, similar to eels, he "sheds" his blue skin during the moment when he becomes pure electricity in the power station. So when he gets pulled into the MCU and then loses his power, his human form is now shown again. And when he starts using the different electric of the new universe, it's simply a different colour because of that.

^That seems like the most realistic explanation that's been given so far.

Maybe Electro could revert to his original look?

The teeth were TASM2, idk about the hair