Can I Appeal a Sentence?

Yes.

The grounds are very limited and appellate courts rarely reverse the trial court’s sentence.

You can appeal a sentence that is unlawful. That means outside the legal range permitted either by statute or by the sentencing code, vindictive, lacks proportionality, is cruel and unusual, was imposed without effective assistance of counsel or beyond the court's jurisdiction.

Very, very, few sentences are overturned by appellate courts. At best you can have the case sent back for re-sentencing.