For the sweat part...
to do it quickly... you can try Alien Skin Eye Candy 3000 plug-ins for Adobe Photoshop. They have a water droplets filter which you can create sweat like effects on the body of your model.
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If you want to do it in Photoshop without plug ins.. you can try this way. (Its just a very rough idea of how I would create sweat effects.. you would really need to play around with this depending on how big your model in the picture is. Sometimes.. you might need to create a few different layers of sweats, you can Scale down and etc...)
I cant really tell you the exact values, and procedures since I cannot see your original image... but I really hope you can get some rough idea from this... :sweatsm:
Create a Displacement Map first
Firstly... Select All (CTRL+A) and Copy (CTRL+C)
Get a new file (CTRL+N) and paste your pict on it (CTRL+V)
And Desaturate the new pic (Image - Adjustment - Desaturate)
And save it as a Displacementmap.PSD on your hard disk, and close the file.
Create Sweat Droplets
Now go back to your original file.
New Layer (SHIFT+CTRL+N)
Reset the swatches (D)
Filter - Render - Clouds
Filter - Render - Difference Clouds (repeat this step for 2~3 times)
Image - Adjustment - Auto Levels
Filter - Sketch - Plaster (I used Image Balance around 39 and Smoothness about 11, but its up to you to decide, play around with the values)
Use the magic wand tool, select the BLACK areas and give a feather radius about 2, and delete.
You should get the water droplets already, now change the blendin mode of that droplets layer to "SoftLight".
Warp the sweat on your Model
Now we're gonna give this layer a bit distortion according to the face of your model.
So go to Filter - Distort - Displace...
H/V scale of 10, Stretch to Fit, and Repeat Edge Pixels, and click on OK to accept it.
And now locate your Displacementmap.PSD file that you have saved previously. And click OK.
Click CTRL+F to reapply this Displace filter again till you are satisfied with the distortion along the shape of your model.
Go to Image - Adjustment - Hue/Saturation and click on "Colorize" checkbox, and drag the HUE slider to get the Blue tone since you want the blue sweats...
Clean Up
Choose the Eraser tool, with the Opacity of 50%.
Clean up some sweats from the parts you want to remove (eg, hair, etc.)
hope it works...
You might need to create a few different sweat layers and play with them, over lap them... scale/transform them till you get the results you hope for. Remember to apply the Displace.. filter only after you scale your sweat layer.
Good luck with your PhotoEditing!
Cheers!