Rose: [after witnessing the Doctor's regeneration] Can you change back?
The Doctor: Do you want me to?
The Doctor: Oh.
Rose: Can you?
The Doctor: No.
[the Doctor is feeling his body just after regenerating.]
The Doctor: Hair! I'm not bald! Ooh... big hair. Sideburns - I've got sideburns! Ooh, really bad skin. Little bit thinner; that's weird. Give me time, I'll get used to it. I... have got a mole. I can feel it. Between my shoulder blades, there's a mole. And it's all right! Love the mole. Go on, then. Tell me... What do you think?