Mosquito bites all over one day before wedding

Antihistamines and calamine lotion are supposed to be good! I also find witch hazel helpful. Have a search online, there are lots of cheap and effective methods.

Will your arms/back be on show? The chances are people won't notice anyway, but if it bothers you a lot, any red/white spots can be covered with a skin tint or concealer (be sure to test it out with a white t shirt so it doesn't transfer on your dress!)

This just happened to me after engagement photos. I never has bitten so badly before.

They have a cortisone cream or spray to stop the pain/itching.
Use benadryl at night and/or non-drowsy allergy pills and ibuprofen during the day. The antihistamines help bring down the reaction.
Use calamine lotion to dry it out after the itching subsides.

If you’ve hired a makeup artist, you can ask them to try airbrushing foundation over any bites that are very red or distracting. The anti itch advice about should help you from itching and keep the red down.

I find benedryl creams works really well, be generous with it. Or you can do calamine lotion, or witch hazel or hydrocortisone cream combined with oral benedryl. A hot bath with oatmeal (you can’t fine packets at any drug store) will help

i heard that if you put ice over them it would help reduce the inflammation

Ice to help inflammation, eucalyptus oil will help as well as witch hazel. Calamine lotion or hydrocortisone cream will help with itching. You could also take a bleach bath. If all else fails, soak in milk or apply cotton balls to them soaked in milk.