any injury for that matter carries the risk of infection whether it is deep or superficial. but our body is capable enough to fight aganist the infection and to protect us unless immunocompromised. the treatment what your mother has recieved is adequate and it there is no need for blood tests or any other tests as all of them will come normal. the blood test and the a test called culture and sensitivity for the infection at the site of injury will be done if there is pus formation at the site of injury.