according to the history you gave seems you have malaligned teeth with teeth in the lower jaw compared to the upper are plced anteriorly and thus put pressure on the lips thus cutting your lips
if not treated may result into canker sore
These are a tooth that may take on the appearance as a result from an unstable bite in the teeth, such as an over- or under-bite.
immediate treatment is to cure the symptoms first.. so go for a gum paint apply 3-4 times and massage
Often something easy such as placing white composite filling material will temporarily improve the appearance. Unfortunately, if the underlying problem is not fixed, the composite usually needs to be replaced periodically as it has a tendency to come off.
Placing a porcelain crown can be a stronger solution, however it requires drilling the tooth and often the porcelain will chip just as easily as the original tooth enamel.
lastly visit an orthodontist and go for an apropriate ortho tratment.