bumps

When Vinny arrived home 6 weeks ago he and Roxy began their staffy play and he kept nipping her on the same spot on her cheek. We took her to the vet and were given antibiotics and ointment as the section had gotten quiet big and it bleeds when Roxy scratches and Vinny keeps getting the same spot. Two weeks since the vet visit and it is no better.

On top of that, she has developed a cluster of small, hard, crusty bumps on her one shoulder. We're hoping it is some sort of heat rash as that is where her harness lies. She has also had a good few open field walks these holidays and may be a grass allergy or something? Nothing has changed diet-wise and she has not gotten into anything she shouldn't. One of the behaviourists we walk with suggested a vet visit to rule out the possibility of her immune system being a bit low (ie extra activity since Vinny arrived + new walks and new walk places).

The bumps don't seem to bother her and she is absolutely normal in herself (happy, exuberant, eating, etc).

Any ideas? We are taking her to the vet tomorrow. Also, she had her last set of puppy injections in June and turns 1 year old this month - so she may be due a booster?