I once saw a bunny at my vet with maggots in a wound
the vet just picked them off and then treated the wound,no pesticide..
I hope you don't have to bring her to HS.
The vet should be able to establish her age,maybe she's older than you think(hopefully!)you don't mention her size.
The eye could be closed,either because she's very young or has an infected eye.
I hope it will work out for this little girl and she can stay with you
Please let us know what happens at the vet