I agree that it is difficult to conceal if the hair is not long enough to comb forward. However, there are ways to decrease the appearance of the recipient zone. Since you are taking a full six weeks away from work you are in a good position to conceal the evidence
1. Keep growing your hair longer. The longer it is the more you can conceal the work performed by combing the hair forward. This is if you have FUSS (strip). If you have FUE then the opposite applies. Allow your hair to grow longer then shave your head for the procedure. Once the procedure is over keep your hair buzzed till you return to work and for the first month or two after your return. Once your new hair starts to grow then you can allow the rest of your hair to grow as well.
2. Visit a tanning bed facility to build up the pigment in your skin before surgery. Darker skin hides recipient trauma (redness) much better than pale skin.
3. Be sure to eat well and take a quality multi-vitamin daily for a few weeks before your procedure. This helps you to be as healthy as possible which means faster healing.
4. Drink lots of water leading up to surgery. Being well hydrated allows the skin to recover faster.
5. Purchase pure aloe liquid (not lotion) as applying this to the recipient zone nightly several days after surgery can also help to dissipate the redness.
If you have your surgery near the beginning of your time off you should be in good position that prevents anyone from seeing obvious signs of hair restoration surgery.