That's not true and is bad advice. Based on OPs before pic, he may benefit a lot from fin, min and derma rolling.
Also the transplanted hair can be affected by DHT and the medications should be considered for post op patients. Also OP is 7.5 months into his post op results and there is more hair still growing in, still four or more months before we see his final results. You haven't seen his donor area either.
We all know that a 1,700 euro surgery of 3,800 grafts is crazy cheap and unlikely to lead to a top result but don't let that interfere with giving OP the best advice possible. He should be discouraged from returning to an unknown hair mill as John posted. His remaining donor hair should be managed by a trusted clinic, but he also needs to consider getting on fin, min and other treatments. All is not lost here.