Modern workers would kill a warble before it reached the skin.
I have seen many warbles, mostly in cattle, but always on the upper some of the host.
When the lump gets as big as your looks, there will be a small partially formed scab in the centre of the lump signifying it is ready to burst out.
Now the gross part is, if you pick that scab off you will see two eyes looking at you. Squeeze and the grub will pop out. They can be quite big!
I remember a friend getting some cattle from Ireland, about three months after arriving they developed lumps along their backs. I knew what it was but owner said it was an allergic reaction to something they had eaten. Got them into the pen and crush and proved him wrong. Best part was the children watching were all saying how gross, but days later were wanting to get them out.
Dr Pimple Popper eat your heart out!