Be specific, tell them what you want. Applied for mine last year and the doctor that I was with gave me a proper telling off for my lack of confidence in letter writing.
My recommendations;
- Remove any other time of your convenience and be specific about what you want. (Isn't two days too little? How are you suppose to gain an insight into medicine in two days - at least a week!)
- In the second paragraph, why derma? If you want to go into derma then specify why, if not then the significance of including dermatology in that sentence is invalid.
Sound good overall.