Hair dying while pregnant ?

I'm 18 weeks today and REALLY want to dye my hair. And no, I'm not some selfish person who wants to dye it for fun knowing it may be harmful to the baby as people say. I have a disease that has bald spots all over my head, and my hair is naturally brown-black. Before I even got pregnant I let it go natural and avoided anymore hair dying or frying to avoid anymore damage to it because i had terrible split ends and want it long and healthy. Anyways; it's been over a year since I last died it and now that it's healthy again and I want it lighter again due to the bald spots.. Not just that reason but also, Because since my hair is so dark it's so easy to spot my bald spots through the dark hairs and when my hair was lighter my self confidence was so much better and it was harder to notice them. I also have a whole layer bald (and starting to grow back finally!!) in my forehead which is the worst because it cants be covered up unless I have a headband on... I look like I have a 10 head instead of a forehead lol.. With the blackish natural hair it looks even bigger and worse too, I found with my light brown hair with some blond in it made it look so much better. I'm having a gender reveal party in a month and meeting some of the fathers family for the first time (he's in the navy and will be coming home for a weekend) so I really don't want them to show or to look ridiculous. I've seen pregnant women get their hair done at salons before and know many that have too; is it really that harmful, especially in the second trimester ? Has anyone done this? And do I need to get a specific kind of dye (I will not go to a salon due to my condition and anxiety and embarrassment over it). Many friends Drs and midwives said box dye is fine as log as you have ventilation in the room; and I know many who used box dues while pregnant and have happy healthy babies today. Of course, I Will be talking to my dr ASAP before I make any decisions however, I just want to see what you ladies recommend as well! No hate please; thank you !!