Hey! I am no pro, but I did Mystic. The tan doesn’t last too long, so you can do it 3-4 days ahead of time and if you hate it it’ll be faded by the time your event comes around. 

I tried it out before doing it for my event, but that’s no help, I realize, as your event is in 10 days. UNLESS you’re willing to get one like today or tomorrow and then another one in a week. But budget and time might prohibit that…

TIPS

• USE THAT LOTION STUFF LIBERALLY. You do not want tanner in your fingernails. 
• check out some instruction videos (google “mystic tan instructions”)
• put plastic on your feet - either booties or use a shower cap (the place i went provided shower caps for your hair but nothing for your feet, so i improvised). dont listen to the people that say hair spray works. it doesnt.
• when you’re done, a few mins after you’re dry, use baby wipes to wipe your hands AND the creases of your wrists. the first time i did it i had lines on my wrists where the tanner had not gotten to.
• HOLD YOUR BREATH, it’s kinda nasty in the booth. but it’s 90 seconds of your life, with 4 breaks to take a breath of air, so you’ll be fine. you can even leave the door to the booth open a crack during the process if you want.
• do a low or middle grade tan, not the darkest they have. you look pale in your pix (no offense! im a ghost!) so i would go with the lightest color so you dont have the risk of turning orange. 
• go naked. you’re all alone in there so who cares? plus then you dont ruin anything and you dont have “tan” lines
• you CANNOT shower or sweat (read: workout) for 12 hours. period.
• you WILL be lighter after showering the first time (12 hours or more later) because the top coat washes away, so dont freak if you are darker than you wanted at first. and remember, it fades fast - only a few days.

anything else i can help with?? let me know! Good luck!!!