Why do my lips keep randomly getting swollen since having juvederm fillers a month ago? (Photos)

I have had juvederm fillers done twice before and had no problems. Weeks After having it done the 3rd time I saw my lip get incredibly swollen. I thought I ate something bad so I took medication given to me from the doctor which helped. After it clearing, again 2 weeks later it happened again whilst being on holiday. I saw a doctor who gave me medication which worked . But now again the swollen lip has returned and it's really getting me upset as I don't know what's causing it. Please help!