If I get 360 lipo/BBL and I have a child after, would this permanently mess up my results or would the results come back?

When considering the timing of cosmetic surgery, it is important to note that the longevity of the result is dependent upon your post op stability. Significant changes in weight can alter results. These changes are difficult to predict but they may require revisionary surgery.
Thus, when considering pre-pregnancy surgery one must be comfortable with the prospect of a compromised outcome. In the case of BBL, the significant weight changes can lead to skin stretch and loss of elasticity. There is also the potential for unintended weight gain which persists post partum.
While it is impossible to predict with certainty how your body will change post partum, it is safe assumption that there may be some changes which can ultimately affect your outcome. 

As always, discuss your concerns with a board certified plastic surgeon (ABPS).

While pregnancy does change your body in multiple ways, the fat cells transferred to the buttocks will still be there after giving birth. This means that the transferred cells will react to changes just like your other fat. 

Hello and thank you for your question, everything will depend on how you care during pregnancy (in terms of food and exercise) and how you continue your care after this, you must maintain a balanced diet and continue your exercise routine, so the results of your surgical procedure should not change. I recommend you to have a personal consult with your plastic surgeon and comment with him about your concerns. All the best!!