Dermatology is a wonderful field. I'd say the most challenging part is being able to diagnose rashes accurately. The majority of what you see will be easy; Acne, seborrheic dermatitis, and acrochordons etc. Skin cancers are also easy because you simply biopsy and the pathology report gives you the diagnosis. The hard part of Dermatology is the hundreds of rare rashes with very minute differences. You need a very keen eye and the ability to recognize how certain pathologies present on differing skin types. Other than that Dermatology has many perks such as no night calls, only a few dermatologic emergencies, and very few medications/creams to remember.
Another challenge of note is getting into a Dermatology residency which is wildly competitive. If you choose this route, study hard!
If you want to get a feel for if you'd be naturally good at identifying skin conditions you could pick up Shelly's 77 Skins Flashcards and give them a whirl. I hope this helps!