Dermal fillers can change the shape of the face in a natural looking way. You have naturally thin lips so adding a bit of volume here would be a great place to start. There are any number of fillers that work nicely (Volbella, Vollure, Juvéderm). Schedule a consultation with a board certified ...
You need to be evaluated in person by your injector. This could be a herpes outbreak which is easy to treat or something more serious. Either way, it isn't something that can be evaluated online.
The honest truth is that there are multiple methods for lip injection and the choice of technique depends on the lip you are injecting. A smart injector will know several methods and choose the one most appropriate for that individual patient, rather than going with a "one size fits all"...