Indulge

Hi.

I wonder if the following sentence is gramatically correct and also I would be grateful If you could let me know if it sounds polite to start a letter with this sentence.

"I am writing to indulge myself in another inquiry."

I want to write to my professor and ask some questions from him. I already asked him some, so this is the second email of mine.

Can anyone think of a better polite begining.

Thanks in advance