How long no tattoo after a skin removal surgery? I'm 6 weeks post op 360° body lift and arm lift.

Typically, plastic surgeons recommend waiting at least 6-12 months after skin removal surgery, such as a 360° body lift and arm lift, before getting a tattoo. While you are currently 6 weeks post-op, it's essential to remember that the body needs sufficient time to heal fully before undergoing any additional procedures like tattooing.
Here are a few reasons why it's advisable to wait:
1. Healing process: Your body needs time to recover from the trauma of surgery. Tattooing involves puncturing the skin with needles, which can introduce bacteria and potentially cause infection. Waiting until your surgical incisions are fully healed reduces the risk of complications.
2. Scar maturation: Surgical scars undergo a process called scar maturation, during which they become less red, raised, and tender. Getting a tattoo over immature scars can interfere with this process and may result in unpredictable healing and changes to the appearance of the tattoo over time.
3. Skin changes: Your skin may undergo changes during the healing process, including changes in texture, thickness, and elasticity. Waiting several months after surgery allows your skin to stabilize, which can help ensure better tattoo results and longevity.
4. Consultation with your surgeon: Before getting a tattoo, it's a good idea to consult with your plastic surgeon. They can assess your healing progress, provide recommendations, and advise you on the best timing for getting a tattoo based on your individual circumstances.
5. Avoiding unnecessary risks: Getting a tattoo too soon after surgery increases the risk of complications such as infection, delayed wound healing, and changes to the appearance of the tattoo. Waiting until your plastic surgeon gives you the go-ahead minimizes these risks and helps ensure a successful outcome.
It's important to prioritize your health and safety during the recovery process. While waiting for several months may seem like a long time, it's crucial to allow your body the necessary time to heal properly before undergoing any additional procedures like tattooing.

The best thing to do would be to ask your surgeon.  He or she knows your individual surgery, skin type, and risk factors better than anyone in this forum.
Early after surgery there is the risk that a new tattoo could cause an infection.  Even after there is no more open wound or scabbing, you are likely to have poor take of the tattoo pigments if there is still swelling, inflammation, and/or remodeling skin collagen.
In most cases, I recommend waiting until the scars have faded and lost their pink color and the tissues are soft (usually 6-12 months) before having a tattoo in the operated area (in your case, the trunk and upper arms).  After major surgery, the body retains excess fluid in general, so for wrists, ankles, and other areas outside of the operated area, I recommend waiting until there is no detectable swelling in the area, usually about 2 months.