I had a BBL 3 weeks ago, have lump and redness, is this an infection, hematoma, or fat necrosis? (Photo)

Even though we cannot rule out any of the possible complications (hematoma, necrosis, infection/abscess) with just a picture, I personally do not feel like this is a hematoma. Hematomas generally appear immediately after trauma (which is the suitcase contact in this case). We don't expect a hematoma a week after trauma. Also, hematomas usually occur together with some bruises. This is more likely to be a fat necrosis or an abscess. What I would do in such a case would be aspirating the lump with a fine needle and check the content. If there is a fluid collection (dead fat or abscess material), then it would better be drained out. 
This situation needs to be followed up by a plastic surgeon. If you can reach your surgeon that's the best, but if you cannot, I strongly advise to seek local professional assistance, as soon as possible. 

Hello! Thank you for your question. This is the issue with medical tourism in regards to cosmetic surgery. The surgery itself is just as important as the follow up care to ensure good results and optimal safe healing. Without an assessment in person it is impossible to say. I do recommend seeing someone in your local area to rule out the possibility of cellulitis (infection) since if this is not dealt with immediately it could become catastrophic.