That is very obviously not the case. Just look at for example Daniels condition, which has gotten a _lot_ better over time. He still has EC, but he has almost no build up at all. And didn't you say yourself that your lips have improved? When a condition can improve, there can obviously be milder and more severe cases.
And I wouldn't even take the affected areas into the equation of how severe ones condition is all that much. One might have a severe case of EC on just the bottom lip, one might have a mild case on the bottom lip etc..