Insect bite

Mummies, any idea what insect bite is this and how to treat it? My 2 yo girl got it from childcare a few times already but this time is especially bad. Doesn't look like normal mosquito bite as it is very swollen and hard to touch, now her entire leg is slightly swollen. It is also very itchy and she keeps scratching it. I have applied mosquito repellent lotion and used mosquito patches on her every day before sending her to childcare but she still got it.