Trim the feathers away from the wound so you can see it better.
If maggots are still coming out, then you'll need to keep rinsing and picking them off.
Possible they may be inside her, if the abdominal cavity is breached, it can happen.
Hopefully this is not the case.
Ivermectin is not going to help.
You can apply a bit of Swat Gel if she's going outside.
Keep the tissue lightly covered with triple antibiotic ointment.
An antibiotic is up to you. Some give them to help with infection, some don't, but the bottom line is the maggots have got to go and the wound cleaned out really well.
Amoxicillin would be a better choice than Tylan50. Sometimes you can find Amoxicillin at
TSC depending on where you live. If Tylan50 is all you have or can get, I would give her a relatively high(er) dose than you would give for respiratory illness.
Tylan has a dose range of 10-40mg/kg given orally 3 times a day, so I'd go for 30-35mg/kg given orally 3times a day for 5 days.
Get some electrolytes into her and see that she eats. Protein (egg, fish, meat) would be good to give in addition to her normal feed.