The same note, one octave up, appears in Fret 11 on the 1st string, but in order to get back to the previous D#/E♭, we have to skip one string and go back three frets this time (follow the top-right green arrow). This happens every time we cross the 2nd string, because of the tuning alteration. Obviously, we could have used another reference point, the note E an octave up, which appears in Fret 12 of the 1st string, but it helps to understand the relationship between the strings that cross the 2nd string.
The specific frequencies you choose to boost will vary from track to track, and especially from genre to genre. It’s common to apply a subtle boost on the high end using a gentle shelf, typically around 8 kHz or so. So be sure you don’t bring back any of that nasty sibilance — and be careful boosting between 3-6 kHz, as it often causes the vocal to sound shrill and harsh.