Which one should I choose as an upgrading course? I am looking at nail artistry, professional make up or photography course. Can anybody help me with it? Thanks in advance.

Beyond these courses, you may also wish to consider baking. Read this guide on how to start your own home baking business.

Opinon:
If money is your consideration:
Professional make-up 1st. Next maybe nail artistry

Why?
Been a freelance event photographer, you no need attend course to be a freelance photographer, just get a DSLR and play with the setting, trial & error can figure it out. Event photography not as stringent as pre-wed photography.
And photography startup make be high, when do event need to get a pro dslr cost $4k-$5k. Not that you need it, sometime is professional image, your cilent will ask.

Nail artistry unless u have a shop else difficult.

Make up. Every wedding bride will want to hire a make up artist, there is a market. Then up sell nail services. This what investment people call core - satelite apply in income source.😆