Is Harry a metamorphagus?

[weasley4granger]

No: HPFGUIDX 90720

In the first book J K Rowling tells us that the morning after Petunia cut 
Harry's hair (badly) he woke up and his hair was back to the same length it had 
been the night before. We were told in Harry Potter and the Order of the 
Phoenix that Tonks could change her appearance at will, just by concentrating 
really hard. Harry would have been concentrating really hard as he was dreading 
going to school the next day (we all know THAT feeling). But Im not totally 
convinced as Harry has many times tried to hide his scar with his fringe, if he 
could (even by accident or without realising it) wouldn't he physically make 
the scar disappear?