Rogaine on transplanted area or old hair area?

There is no data to suggest when you should resume Rogaine or where you should apply it.  Most physicians suggest you resume Rogaine 48 to 72 hours after a hair transplant.  You probably don't want to massage the grafts until the 7th day, however.  Patients have resumed Rogaine after 48 to 72 hours for many years so it should definitely be safe after 2 week.We really don't know the specific mechanism of action for Minoxidil.  There are many theories regarding how it work and why it works.  It may work in multiple pathways.  It helps to promote the anagen phase of hair and prolong the anangen duration.  It slows down hair loss.  Used in conjunction with finasteride, it is highly beneficial.  I do not think there is any evidence that it will speed up the growth of your grafts or improve the results from your grafts.  You might also consider low level laser therapy.The second part of your question relates to a hair solution and I would assume micro needling to deliver the product.  I would assume the stamp puts tiny pin prick holes in your scalp.  It's really hard to say if micro needling before the grafts have begun to grow is positive or negative in the grafted area.  We often do micro needling in the grafted area at the time of surgery, and it has been done after a procedure.  The needles we use are 1 mm deep and the stem cells are usually 0.8 to 1.6 mm deep.  There are also stem cells at the junction of the arrector pili muscle and the epidermis and of course a deeper batch near the bulb.  I do not think that micro needling damages the grafts, but there have been no studies on micro needling to determine whether it is positive, negative, or of no affect.  Finally, i do not know what is in the Skin Solutions product so I cannot comment on how safe this is.  I assume you are using it as a form of mesotherapy  

You trusted your doctor for your surgery, you should follow your doctors recommendations. Every doctor has their specific post op care. It is also a good idea to follow up with your doctor.

Minoxidil does two good things; it protects existing hairs against future hair loss and strengthens existing miniaturised hairs by increasing their caliber. It theoretically should not have significant effect on newly transplanted hairs, although it should not do any harm either. If the transplanted area has some existing hairs then it will be beneficial to apply minoxidil on those areas. If the transplanted area has only transplanted hairs then minoxidil should not have a significant effect on those areas.

It's good idea to follow your surgeon's instructions. If your surgeon wants you to only use it on the naive hairs, then only use it on the naive hairs. In general, Rogaine can be used on both original and newly transplanted hairs. In some cases, it may speed up the growth of transplanted hairs - but there's no evidence yet that it promotes survival of grafts or changes long term results

I ran an experiment some years ago where I put Rogaine (Minoxidil) on half of the head and not on the other side. Twelve patients were done and there was no difference in the growth one side compared to the other. I concluded minoxidil has nothing to offer when the transplant was done correctly. 

It is a good idea to use a medical regiment routine to keep your native hair, it may actually help with hair growth as well.  Rogaine can be used in both areas after you are completely healed.