I think my lawyer screwed me up. He told me that my H1B was approved but in the I-797C, it says that my change of status was denied! Can I appeal this?
Yes, this may be something that should be appealed but without more information about you case, I don’t see any evidence that your lawyer made a mistake. The requirements to obtain an H1B approval and a change of status are completely separate. In order to show that you qualify to change your status, you must show that you were in a valid nonimmigrant status at the time you filed your H1B petition AND if your H1B start date was October 1, that your status was valid through October 1 or that you qualified for an exception such as the F1 cap gap rule.