Would a revision rhinoplasty fix this or could filler provide symmetry? (Photos)

Seems to me there is here a wrong approach, you are not a case for filing down anything, for corticosteroids injected or for fillers; bear with me and get well these concepts:
-corticosteroids destroy tissue when injected randomly under the skin, they are not anti-inflammatory in those cases, just corrode and produce dips, irregulrities and skin atrophy or yellow blemishes; research on this and you'll find out a lot
-fillers? what for? to get lumps? augment your nose? no point, but beware: they produce blindness, yes irreversible vision loss, if applied in the periorbital and nasal area, do also research on this
-you don't have scar tissue at the nasal base, just happens you lack properly located osteotomies at Joseph's angle: the very right junction of nose and maxilla

Besides, you have open roof, middle vault collapse, inverted V, pinched look, unsupported nasal valve, alar rim retraction, untreated boxy tip, etc.

This is a case for a difficult, comprehensive but in good hands very rewarding revision rhinoplasty, do research well the surgeon's experience, talent and passion for fine work on difficult cases; do perform dozens of in person and online consultations before moving forward.

In the link associated to this answer you can find further information and images related to your problems.

Hello and thank you for your question. Based on your photographs, you are a great candidate for a revision rhinoplasty. Maneuvers for your surgery would include placement of extended spreader grafts to help improve your mid vault symmetry, tip refinement, placement of extended alar contour grafts to help improve nostril symmetry, among other maneuvers. With good surgical technique, you could have an outstanding result. I recommend that you seek consultation with a qualified board-certified rhinoplasty surgeon who can evaluate you in person.

Best wishes and good luck.

Richard G. Reish, M.D.
Harvard-trained plastic surgeon