I made a mistake...

So let me first say that this is my firat time growing and I've definitely been learning on the fly which probably isn't the smartest method. I have a pretty good indoor setup for a solo plant (600 w purple light, reflective tent, light timer, etc) and my plant was doing surprisingly well into its second week of flowering. I took a week long vacation and had a friend checking in on my plant for me while I was away, and came home to a fairly healthy looking plant...as well as an infestation of fungus gnats. In my panic I grabbed the "Off" bugspray from my bag and sprayed it around my room, and sprayed a small squirt into my grow tent. The next morning, I wake up to this (see pictures).

I know now that this was not a very smart idea. Clearly this stuff isn't for plants. I have already removed one of my 4 tops that got the worst if it, as well as a few leaves near the middle that were totally dead. I also removed as much of the soil around the roots as i could and replaced it with fresh, maggot free spoil. Now I'm just wondering if there's any way for me to still come out of this with any type of yield, or is it totally unsalvageable?

Any advice is more than welcome, but save the lectures. I feel bad enough already lol.

Hard to tell. 2nd week of flower, plant looks quite small. If in veg, it would bounce back. 2nd week flower... although early, whats dead is dead but see how it responds over the next week. Looking for promising new healthy growth. If you had a lot of fungus gnats, they most likely already have their larvae in your soil. You'll need to treat as that larvae will kill your plant faster since it's already stressed.