Has any mamas in this group tried to relactate and done it successfully?

I gave up breastfeeding and switched to formula when my baby was 3 weeks. He is now 5 weeks + 3 days. I found out today he has a cow milk allergy (the doctor switched his formula to enfamil nutramigen a+ with lgg) I don’t usually eat dairy so I have no problem cutting it out completely so I am feeling like I need to try and start giving him breastmilk again if possible.

I pumped for the first time in 2 weeks (20 minutes) today and produced around 2 ounces. Is this a good sign that I could successfully relactate?

Also.. have any mamas breastfed when baby had an allergy?